Use java runner for cache

.github/workflows/maven.yml

@@ -26,25 +26,14 @@ jobs:
       # Pull changes
       - uses: actions/checkout@v2.3.4
 
-      # Cache artifacts - however this has the downside that we don't get notified of
-      # artifact resolution failures like invalid repository
-      # Nevertheless the repositories should be more stable and it makes no sense to pull
-      # a same version every time
-      # A dry run would make more sense
-      - uses: actions/cache@v2.1.4
-        with:
-          path: ~/.m2/repository
-          key: ${{ runner.os }}-maven-${{ hashFiles('**/pom.xml') }}
-          restore-keys: |
-            ${{ runner.os }}-maven-
-
       # Setup Java
       - name: Set up JDK
-        uses: actions/setup-java@v2.1.0
+        uses: actions/setup-java@v2.3.0
         with:
           distribution: 'adopt'
           # Use Java 11, because it's minimum required version
           java-version: 11
+          cache: 'maven'
 
       # Build and test (included in package)
       - name: Build with Maven and test