Support for `uv` Package Manager Caching

[mgaitan]

Description
Hey there! I'm suggesting we add caching support for the uv package manager in setup-python. uv (uv pip command currently) is a drop-in replace for pip, using requirements.txt or any other input file that pip supports for dependencies definitions. The only difference is its cache directory: setup-python uses the output of pip cache dir to find the cache directory, but uv uses uv cache dir instead (see astral-sh/uv#1734). It should be a straightforward addition that could help projects using uv.

Justification
uv is 10-100x faster than pip. There is a lot of interest from the community to use this new tool in CI environments (e.g astral-sh/uv#1386)

Are you willing to submit a PR?
Yep! Happy to help out and get my hands dirty with a PR to make this happen. However, I'm far of being a Typescript expert.

[nschloe]

You could also just cache the uv cache directory, e.g.,

      - uses: actions/cache@v4
        id: cache-uv
        with:
          path: ~/.cache/uv
          key: ${{ runner.os }}-python-${{ matrix.python-version }}-uv

[acostapazo]

You could also just cache the uv cache directory, e.g.,

      - uses: actions/cache@v4
        id: cache-uv
        with:
          path: ~/.cache/uv
          key: ${{ runner.os }}-python-${{ matrix.python-version }}-uv

I have just tested this solution and I think it is not worth using it when your requirements are large packages.

I've added the cache in my public playground with alice-biometrics/uv-playground@14871e8

And run a workflow to test what happens when run without cache: https://github.com/alice-biometrics/uv-playground/actions/runs/8046635708/job/21974

241996

surprisingly, the size of the cache is very large, so it takes a long time to save in the post-cache.

Then, I run it again to test how works with a saved cache: https://github.com/alice-biometrics/uv-playground/actions/runs/8046670133/job/21974345476

The installation time is extremely fast, however, it takes the same amount of time to retrieve the cache as it does to install in a fresh environment with uv.

Example of a workflow without uv cache: https://github.com/alice-biometrics/uv-playground/actions/runs/7986874748/job/21808164311

[akx]

Heh, I actually wrote a PR that implements this (before this issue, to boot), but no actions/setup-python maintainer seems to have seen it: #818