Implement cache-dependency-path equivalent

[richardsheridan]

I was about to post this issue over in baipp but this might be a better place for it.

The default cache key ${{runner.os}}-uv is not fine-grained enough to work with a heterogeneous CI/CD pipeline with separated build and test steps, because the requirements to build may be very different from the requirements to run and test. since baipp runs first, it will have a cache miss and save the uv cache for the build step, then any subsequent run using setup-cached-uv will have a cache hit, but only primed for the build dependencies and unable to update the cache with additional test dependencies.

Hopefully setup-python will eventually have cache: uv but until then it would be swell if I could add:

- uses: hynek/setup-cached-uv
  with:
    cache-dependency-path: '**/requirements-dev.txt'

which would result in cache keys like:

setup-cached-uv-Linux-22.04-Ubuntu-python-3.12.2-de25a2691d32d697d64ac0f45eb15fbab0ef7c4ca684a123bb5ec913fb6498d0