Summary

Addresses #175

Add a new include-free-threaded input that, when set to 'true', appends free-threaded Python siblings (e.g. 3.14t) inline after each matching version in the supported_python_classifiers_* outputs, for Python 3.14 and later.
The feature is entirely opt-in and has no effect on existing workflows.

The tests pass on my fork, and include tests for 3.14t and 3.15t for argon2-cffi-bindings, as expected.

From the issue description, it wasn't clear to me how to handle the presence of the Programming Language :: Python :: Free Threading trove classifier. Do you think the action should raise an error if the option is set but the trove classifier does not exist?

Background

I am adopting baipp (thanks for this package!) for a library (oct2py) that depends on numpy/scipy, and I'd like for the generated test matrix to include 3.14t.

Pull Request Check List

• I acknowledge this project's AI policy.
• This pull requests is not from my main branch.
  • Consider granting push permissions to the PR branch, so maintainers can fix minor issues themselves without pestering you.
• The changes are somehow exercised by our CI workflows such that it's possible to at least visually confirm they're doing what they're supposed to do.
• The documentation has been updated.
  • New inputs/outputs have been added to README.md.
  • Documentation in .md files is written using semantic newlines.
• Changes have been added to CHANGELOG.md