v3.2.0 🌈 Support requirements.txt as `version-file`

Changes

With this release you can also use a file in requirements.txt format instead of pyproject.toml for the input version-file.
The file ending decides which parser gets used, so make sure the filenames end in *.txt or *.toml

Thank you @daveisfera

🐛 Bug fixes

• Fix version-file input @eifinger (#72)

🚀 Enhancements

• Support requirements.txt for version-file @daveisfera (#68)

🧰 Maintenance

• Run npm install as part of npm run all @eifinger (#75)
• Make it clearer how to fix lint errors @eifinger (#74)
• Run update-known-checksums every night @eifinger (#73)

📚 Documentation

• Refactor internal function names @eifinger (#76)