(cherry picked from commit bdb81a8)

Motivation for this change

Backport for 18.09 as stated in the original PR

1. we add a lot of features into Trezor and these are not accessible if a user has an older version of python-trezor leading to frustration

2. I assume NixPkgs Electrum maintainers don't backport security patches individually, but rather the whole package is being updated to the newest stable release. This release might already be depending on the new python-trezor package, using the new API, etc. so it makes sense to upgrade the whole package for python-trezor too.

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nox --run "nox-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Determined the impact on package closure size (by running nix path-info -S before and after)
• Assured whether relevant documentation is up to date
• Fits CONTRIBUTING.md.