Dependency updates round 1

[matthewhughes934]

First round of upstreaming some improvements, mostly around
dependencies, from https://github.com/matthewhughes934/isort-fork

• Update typing for setuptools

  The inspiration for this change was the following warning from poetry:

    Warning: The locked version 0.1.3 for types-pkg-resources is a yanked
    version. Reason for being yanked: Use types-setuptools instead
  

  Following that, adding types-setuptools allowed the removal of some
  type: ignore comments, which then lead to a single issue needing to be
  fixed:

    tests/unit/test_setuptools_command.py:8: error: Argument 1 to "ISortCommand" has incompatible type "distutils.dist.Distribution"; expected "setuptools.dist.Distribution"  [arg-type]
  

• Remove some flake8 exceptions

  Mostly as a matter of consistency. For isort/__init__.py this
  exception looks to not be needed since
  be0fbd0

  An exception is kept in pace for an example file in tests as the
  contents of the file are just for testing.

• Restore setuptools as optional dependency

  This looks to have been accidentally removed with
  f7a6b0e, setuptools is still required
  in isort.setuptools_commands

• Drop some unused dependencies

  • ipython was removed with 49b41a5
  • smmap2 looking at the history with git log -G smmap --name-only --oneline suggests this was only ever defined in
    poetry.lock/pyproject.toml. Given this is a library and not
    providing something extra like e.g. a flake8 plugin it should be
    safe to remove

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 99.12%. Comparing base (4eeb37a) to head (b30c9b1).
Report is 31 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2325      +/-   ##
==========================================
- Coverage   99.15%   99.12%   -0.04%     
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  Files          39       39              
  Lines        3091     3097       +6     
  Branches      748      787      +39     
==========================================
+ Hits         3065     3070       +5     
  Misses         15       15              
- Partials       11       12       +1