Support `working-directory`

Per the title it would be great if this supported working-directory to set the folder where you are running code for a step

    - name: Save ${{ inputs.target }} 
      if: always()
      working-directory: ${{ inputs.workdir }}
      uses: actions/cache/save@v4.2.0
      with:
        path: "file.tar.gz"
        key: ${{ inputs.target }}-corpus-${{ github.run_id }}

The path is so strict that when folder structure is not always static it makes working with save / restore very difficult.

No files, tests, or entry points are named in the issue. Start by locating the cache save and restore action inputs and path handling, then verify that a working-directory input scopes relative paths as shown in the example without changing existing behavior.