Add caching of gradle packages on CI

.github/workflows/check.yml

@@ -27,6 +27,13 @@ jobs:
           key: ${{ runner.os }}-sonar
           restore-keys: ${{ runner.os }}-sonar
 
+      - name: Cache Gradle packages
+        uses: actions/cache@v1
+        with:
+          path: ~/.gradle/caches
+          key: ${{ runner.os }}-gradle-${{ hashFiles('**/*.gradle') }}
+          restore-keys: ${{ runner.os }}-gradle
+
       - name: Run tests
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}