fix(deps): bump actions/cache from 2.1.5 to 2.1.6

Bumps [actions/cache](https://github.com/actions/cache) from 2.1.5 to 2.1.6.
- [Release notes](https://github.com/actions/cache/releases)
- [Commits](actions/cache@v2.1.5...v2.1.6)

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

.github/workflows/ci.yml

@@ -34,7 +34,7 @@ jobs:
         run: echo "::set-output name=dir::$(npm config get cache)"
 
       - name: Restore cached node_modules 🤷‍♂️
-        uses: actions/[email protected].5
+        uses: actions/[email protected].6
         with:
           path: ${{ steps.npm-cache.outputs.dir }}
           key: ${{ runner.os }}-node-${{ hashFiles('**/package-lock.json') }}