Use built-in Maven cache of actions/setup-java

Author: joschi

.github/workflows/pr.yml

@@ -27,12 +27,7 @@ jobs:
         with:
           distribution: 'zulu'
           java-version: ${{ matrix.java_version }}
-      - uses: actions/cache@v2.1.7
-        with:
-          path: ~/.m2/repository
-          key: ${{ runner.os }}-maven-${{ hashFiles('**/pom.xml') }}
-          restore-keys: |
-            ${{ runner.os }}-maven-
+          cache: 'maven'
       - name: Cache SonarCloud packages
         uses: actions/cache@v2.1.7
         if: ${{ env.SONAR_TOKEN != null && env.SONAR_TOKEN != '' && matrix.java_version == '11' }}