Motivation for this change

noticed it was broken while reviewing #70779

before:

slither --help
Traceback (most recent call last):
  File "/nix/store/avcqq2i4qxrq0q88lcfjcqwp5kwncsc0-python3.7-slither-analyzer-0.3.0/bin/.slither-wrapped", line 7, in <module>
    from slither.__main__ import main
  File "/nix/store/avcqq2i4qxrq0q88lcfjcqwp5kwncsc0-python3.7-slither-analyzer-0.3.0/lib/python3.7/site-packages/slither/__main__.py", line 12, in <module>
    from pkg_resources import iter_entry_points, require
ModuleNotFoundError: No module named 'pkg_resources'

after:

$ slither --help
usage: slither.py contract.sol [flag]

Slither

positional arguments:
....

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 nix-review --run "nix-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)
• Ensured that relevant documentation is up to date
• Fits CONTRIBUTING.md.

Notify maintainers

cc @