GitHub workflows: Use Java version in matrix, cache functionality of actions/setup-java@v2 (#614)

* Fix GitHub workflows not using Java version in matrix

* Use cache functionality of actions/setup-java@v2

.github/workflows/maven.yml

@@ -20,17 +20,12 @@ jobs:
 
     steps:
       - uses: actions/checkout@v2
-      - name: Set up JDK 1.8
-        uses: actions/setup-java@v1
+      - name: Set up JDK ${{ matrix.java }}
+        uses: actions/setup-java@v2
         with:
-          java-version: 1.8
-      - name: Cache local Maven repository
-        uses: actions/cache@v2
-        with:
-          path: ~/.m2/repository
-          key: ${{ runner.os }}-maven-${{ hashFiles('**/pom.xml') }}
-          restore-keys: |
-            ${{ runner.os }}-maven-
+          distribution: 'zulu'
+          java-version: ${{ matrix.java }}
+          cache: 'maven'
       - name: Build with Maven
         run: ./mvnw clean install -B -U -P sonar
       - uses: codecov/codecov-action@v1