This fixes CVE-2018-10184 a potential remote denial of service in the
http/2 module. The version bump also includes various other changes that
are described in the changelog [1]:

2018/05/18 : 1.8.9
    - BUG/MINOR: pattern: Add a missing HA_SPIN_INIT() in pat_ref_newid()
    - BUG/MAJOR: channel: Fix crash when trying to read from a closed socket
    - BUG/MINOR: log: t_idle (%Ti) is not set for some requests
    - BUG/MEDIUM: lua: Fix segmentation fault if a Lua task exits
    - MINOR: h2: detect presence of CONNECT and/or content-length
    - BUG/MEDIUM: h2: implement missing support for chunked encoded uploads
    - BUG/MINOR: lua/threads: Make lua's tasks sticky to the current thread
    - BUG/MINOR: config: disable http-reuse on TCP proxies
    - BUG/MINOR: checks: Fix check->health computation for flapping servers
    - BUG/MEDIUM: threads: Fix the sync point for more than 32 threads
    - BUG/MINOR: lua: Put tasks to sleep when waiting for data
    - DOC/MINOR: clean up LUA documentation re: servers & array/table.
    - BUG/MINOR: map: correctly track reference to the last ref_elt being dumped
    - BUG/MEDIUM: task: Don't free a task that is about to be run.
    - BUG/MINOR: lua: schedule socket task upon lua connect()
    - BUG/MINOR: lua: ensure large proxy IDs can be represented
    - BUG/MEDIUM: http: don't always abort transfers on CF_SHUTR
    - BUG/MEDIUM: pollers: Use a global list for fd shared between threads.
    - BUG/MEDIUM: ssl: properly protect SSL cert generation
    - BUG/MINOR: spoe: Mistake in error message about SPOE configuration

2018/04/19 : 1.8.8
    - BUG/MEDIUM: threads: Fix the max/min calculation because of name clashes
    - BUG/MEDIUM: connection: Make sure we have a mux before calling detach().
    - BUG/MINOR: http: Return an error in proxy mode when url2sa fails
    - BUG/MEDIUM: kqueue: When adding new events, provide an output to get errors.
    - BUG/MINOR: cli: Guard against NULL messages when using CLI_ST_PRINT_FREE
    - MINOR: cli: Ensure the CLI always outputs an error when it should
    - DOC: lua: update the links to the config and Lua API
    - BUG/CRITICAL: h2: fix incorrect frame length check

2018/04/07 : 1.8.7
    - BUG/MAJOR: cache: always initialize newly created objects
    - MINOR: servers: Support alphanumeric characters for the server templates names

2018/04/05 : 1.8.6
    - BUG/MINOR: lua: the function returns anything
    - BUG/MINOR: lua funtion hlua_socket_settimeout don't check negative values
    - BUILD/MINOR: fix build when USE_THREAD is not defined
    - MINOR: cli/threads: make "show fd" report thread_sync_io_handler instead of "unknown"
    - MINOR: cli: make "show fd" report the mux and mux_ctx pointers when available
    - BUILD/MINOR: cli: fix a build warning introduced by last commit
    - BUG/MINOR: hpack: fix harmless use of uninitialized value in hpack_dht_insert
    - CLEANUP: h2: rename misleading h2c_stream_close() to h2s_close()
    - MINOR: h2: provide and use h2s_detach() and h2s_free()
    - BUG/MAJOR: h2: remove orphaned streams from the send list before closing
    - MINOR: h2: always call h2s_detach() in h2_detach()
    - MINOR: h2: fuse h2s_detach() and h2s_free() into h2s_destroy()
    - BUG/MEDIUM: h2/threads: never release the task outside of the task handler
    - BUG/MEDIUM: h2: don't consider pending data on detach if connection is in error
    - BUILD/MINOR: threads: always export thread_sync_io_handler()
    - BUG/MEDIUM: h2: always add a stream to the send or fctl list when blocked
    - BUG/MINOR: checks: check the conn_stream's readiness and not the connection
    - BUG/MINOR: email-alert: Set the mailer port during alert initialization
    - BUG/MINOR: cache: fix "show cache" output
    - BUG/MINOR: fd: Don't clear the update_mask in fd_insert.
    - BUG/MAJOR: cache: fix random crashes caused by incorrect delete() on non-first blocks
    - BUG/MINOR: spoe: Initialize variables used during conf parsing before any check
    - BUG/MINOR: spoe: Don't release the context buffer in .check_timeouts callbaclk

2018/03/23 : 1.8.5
    - BUG/MINOR: threads: fix missing thread lock labels for 1.8
    - BUG/MEDIUM: ssl: Don't always treat SSL_ERROR_SYSCALL as unrecovarable.
    - BUG/MEDIUM: ssl: Shutdown the connection for reading on SSL_ERROR_SYSCALL
    - BUG/MINOR: init: Add missing brackets in the code parsing -sf/-st
    - BUG/MINOR: ssl/threads: Make management of the TLS ticket keys files thread-safe
    - BUG/MEDIUM: http: Switch the HTTP response in tunnel mode as earlier as possible
    - BUG/MEDIUM: ssl/sample: ssl_bc_* fetch keywords are broken.
    - DOC: lua: new prototype for function "register_action()"
    - DOC: cfgparse: Warn on option (tcp|http)log in backend
    - BUG/MINOR: debug/pools: properly handle out-of-memory when building with DEBUG_UAF
    - MINOR: debug/pools: make DEBUG_UAF also detect underflows
    - BUG/MINOR: h2: Set the target of dbuf_wait to h2c
    - MINOR: stats: display the number of threads in the statistics.
    - BUG/MEDIUM: h2: always consume any trailing data after end of output buffers
    - BUG/MEDIUM: buffer: Fix the wrapping case in bo_putblk
    - BUG/MEDIUM: buffer: Fix the wrapping case in bi_putblk
    - Revert "BUG/MINOR: send-proxy-v2: string size must include ('\0')"
    - MINOR: systemd: Add section for SystemD sandboxing to unit file
    - MINOR: systemd: Add SystemD's Protect*= options to the unit file
    - MINOR: systemd: Add SystemD's SystemCallFilter option to the unit file
    - MINOR/BUILD: fix Lua build on Mac OS X
    - BUILD/MINOR: fix Lua build on Mac OS X (again)
    - BUG/MINOR: session: Fix tcp-request session failure if handshake.
    - CLEANUP: .gitignore: Ignore binaries from the contrib directory
    - BUG/MINOR: unix: Don't mess up when removing the socket from the xfer_sock_list.
    - BUG/MEDIUM: h2: also arm the h2 timeout when sending
    - BUG/MINOR: cli: Fix a crash when passing a negative or too large value to "show fd"
    - CLEANUP: ssl: Remove a duplicated #include
    - CLEANUP: cli: Remove a leftover debug message
    - BUG/MINOR: cli: Fix a typo in the 'set rate-limit' usage
    - BUG/MEDIUM: fix a 100% cpu usage with cpu-map and nbthread/nbproc
    - BUG/MINOR: force-persist and ignore-persist only apply to backends
    - BUG/MEDIUM: spoe: Remove idle applets from idle list when HAProxy is stopping
    - BUG/MEDIUM: threads/unix: Fix a deadlock when a listener is temporarily disabled
    - BUG/MAJOR: threads/queue: Fix thread-safety issues on the queues management
    - BUG/MINOR: dns: don't downgrade DNS accepted payload size automatically
    - BUG/MINOR: seemless reload: Fix crash when an interface is specified.
    - BUG/MINOR: cli: Fix a crash when sending a command with too many arguments
    - BUILD: ssl: Fix build with OpenSSL without NPN capability
    - BUG/MINOR: spoa-example: unexpected behavior for more than 127 args
    - BUG/MINOR: lua: return bad error messages
    - BUG/MEDIUM: tcp-check: single connect rule can't detect DOWN servers
    - BUG/MINOR: tcp-check: use the server's service port as a fallback
    - BUG/MEDIUM: threads/queue: wake up other threads upon dequeue
    - MINOR: log: stop emitting alerts when it's not possible to write on the socket
    - BUILD/BUG: enable -fno-strict-overflow by default
    - DOC: log: more than 2 log servers are allowed
    - DOC: don't suggest using http-server-close
    - BUG/MEDIUM: h2: properly account for DATA padding in flow control
    - BUG/MINOR: h2: ensure we can never send an RST_STREAM in response to an RST_STREAM
    - BUG/MINOR: listener: Don't decrease actconn twice when a new session is rejected

[1] https://www.haproxy.org/download/1.8/src/CHANGELOG

Haproxy 1.8.9