build(deps): bump actions/cache from 2.1.6 to 2.1.7

Bumps [actions/cache](https://github.com/actions/cache) from 2.1.6 to 2.1.7.
- [Release notes](https://github.com/actions/cache/releases)
- [Commits](actions/cache@v2.1.6...v2.1.7)

---
updated-dependencies:
- dependency-name: actions/cache
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

.github/workflows/tests.yml

@@ -23,7 +23,7 @@ jobs:
 
     - name: Cache Homebrew Bundler RubyGems
       id: cache
-      uses: actions/[email protected].6
+      uses: actions/[email protected].7
       with:
         path: ${{ steps.set-up-homebrew.outputs.gems-path }}
         key: ${{ runner.os }}-rubygems-${{ steps.set-up-homebrew.outputs.gems-hash }}