Bump actions/cache from 1 to 2.1.6

Bumps [actions/cache](https://github.com/actions/cache) from 1 to 2.1.6.
- [Release notes](https://github.com/actions/cache/releases)
- [Commits](actions/cache@v1...v2.1.6)

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

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

Author: dependabot[bot]

.github/workflows/sonarcloud.yml

@@ -20,13 +20,13 @@ jobs:
         with:
           java-version: 11
       - name: Cache SonarCloud packages
-        uses: actions/cache@v1
+        uses: actions/cache@v2.1.6
         with:
           path: ~/.sonar/cache
           key: ${{ runner.os }}-sonar
           restore-keys: ${{ runner.os }}-sonar
       - name: Cache Gradle packages
-        uses: actions/cache@v1
+        uses: actions/cache@v2.1.6
         with:
           path: ~/.gradle/caches
           key: ${{ runner.os }}-gradle-${{ hashFiles('**/*.gradle') }}