build(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](https://github.com/actions/cache/compare/v2.1.5...v2.1.6)

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/ci.yaml

@@ -24,7 +24,7 @@ jobs:
         run: echo "::set-output name=dir::$(yarn cache dir)"
 
       - name: Cache yarn cache
-        uses: actions/cache@v2.1.5
+        uses: actions/cache@v2.1.6
         id: cache-yarn-cache
         with:
           path: ${{ steps.yarn-cache-dir-path.outputs.dir }}
@@ -34,7 +34,7 @@ jobs:
 
       - name: Cache node_modules
         id: cache-node-modules
-        uses: actions/cache@v2.1.5
+        uses: actions/cache@v2.1.6
         with:
           path: node_modules
           key: ${{ runner.os }}-${{ matrix.node-version }}-nodemodules-${{ hashFiles('**/yarn.lock') }}