Allow constraining linter versions in GitHub Action configuration

[akaihola]

Fixes #337. Being tested in akaihola/pgtricks#18.

Linter support was added in #313.

[akaihola]

The workflow in akaihola/pgtricks#18 seems to work. I have this in .github/workflows/python-package.yml:

    - uses: akaihola/darker@gh-action-linter-versions
      with:
        options: --verbose --check --diff --isort
        revision: origin/master...
        lint: flake8 == 4.0.0 , pylint==2.13.2

The versions for flake8 and pylint are one patch version older than the newest releases. And sure enough, I see this in the log for the workflow:

Successfully installed astroid-2.11.2 black-22.3.0 click-8.1.0 darker-1.4.2 dill-0.3.4 flake8-4.0.0
isort-5.10.1 lazy-object-proxy-1.7.1 mccabe-0.6.1 mypy-extensions-0.4.3 pathspec-0.9.0 platformdirs-2.5.1
pycodestyle-2.8.0 pyflakes-2.4.0 pylint-2.13.2 toml-0.10.2 tomli-2.0.1 wrapt-1.14.0

So flake8==4.0.0 and pylint==2.13.2 were indeed installed.

Note that the workflow fails on purpose – I added extra spaces so reformatters and linters would fail and show the log.

[roniemartinez]

Awesome! 🚀