Update Github cache action from v1 to v2

This will update this Github cache actions library from version v1 to v2.
The new version has better performance and caching abilities.

Release notes available at:
https://github.com/actions/cache/releases/tag/v2.0.0


Issue: None
PR: #269

.github/workflows/actions.yml

@@ -31,13 +31,13 @@ jobs:
         with:
           java-version: ${{ matrix.java }}
       - name: Cache Gradle
-        uses: actions/cache@v1
+        uses: actions/cache@v2
         with:
           path: ~/.gradle/caches/
           key: ${{ runner.os }}-gradle-${{ hashFiles('**/*.gradle*') }}
           restore-keys: ${{ runner.os }}-gradle-
       - name: Cache Sonar
-        uses: actions/cache@v1
+        uses: actions/cache@v2
         if: matrix.java == '11' && matrix.os == 'ubuntu'
         with:
           path: ~/.sonar/cache/