title: Clear cache in GitHub Actions
body: <p>I am working on an R package and using GitHub Action (GHA) as a Continuous Integration (CI) provider. I cache R packages (dependencies) by using <a href="https://github.com/actions/cache" rel="noreferrer"><code>actions/cache</code></a>. And now I want to clear all cache. How can I do that?</p>
  <hr />
  
  A part of GHA Workflow I use:
  <pre class="lang-yaml prettyprint-override"><code>on: push
  
  name: R-CMD-check
  
  jobs:
    R-CMD-check:
      runs-on: ${{ matrix.config.os }}
  
      name: ${{ matrix.config.os }} (${{ matrix.config.r }})
  
      strategy:
        fail-fast: false
        matrix:
          config:
            # - {os: windows-latest, r: 'devel'}
            - {os: macOS-latest,   r: 'release'}
  
      env:
        R_REMOTES_NO_ERRORS_FROM_WARNINGS: true
        RSPM: ${{ matrix.config.rspm }}
        GITHUB_PAT: ${{ secrets.GITHUB_TOKEN }}
  
      steps:
        - uses: actions/checkout@v2
  
        - uses: r-lib/actions/setup-r@master
  
        - name: Query dependencies
          run: |
            repos &lt;- c(&quot;https://r-hyperspec.github.io/hySpc.pkgs/&quot;, getOption(&quot;repos&quot;))
            saveRDS(&quot;remotes::dev_package_deps(dependencies = TRUE)&quot;, &quot;.github/depends.Rds&quot;, version = 2)
            writeLines(sprintf(&quot;R-%i.%i&quot;, getRversion()$major, getRversion()$minor), &quot;.github/R-version&quot;)
          shell: Rscript {0}
  
        - name: Cache R packages
          if: runner.os != 'Windows'
          uses: actions/cache@v1
          with:
            path: ${{ env.R_LIBS_USER }}
            key: ${{ runner.os }}-${{ hashFiles('.github/R-version') }}-1-${{ hashFiles('.github/depends.Rds') }}
            restore-keys: ${{ runner.os }}-${{ hashFiles('.github/R-version') }}-1-
  
        - name: Install dependencies
          run:   remotes::install_deps(dependencies = TRUE)
          shell: Rscript {0}
  
        - name: Session info
          run: |
            options(width = 100)
            pkgs &lt;- installed.packages()[, &quot;Package&quot;]
            sessioninfo::session_info(pkgs, include_base = TRUE)
          shell: Rscript {0}
  </code></pre>