Bump actions/cache from 2.1.6 to 2.1.7 (#62)

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]>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/workflows/unit-test.yml

@@ -38,7 +38,7 @@ jobs:
 
       - name: cache-googletest
         id: cache-googletest
-        uses: actions/[email protected].6
+        uses: actions/[email protected].7
         with:
           path: googletest-install-${{ matrix.image }}
           key: cache-googletest-${{ matrix.image }}