Update GitHub build to Java 21

.github/workflows/build.yml

@@ -11,22 +11,22 @@ jobs:
     name: Build
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
         with:
           fetch-depth: 0  # Shallow clones should be disabled for a better relevancy of analysis
-      - name: Set up JDK 17
-        uses: actions/setup-java@v3
+      - name: Set up JDK 21
+        uses: actions/setup-java@v4
         with:
           distribution: 'adopt'
-          java-version: 17
+          java-version: '21'
       - name: Cache SonarCloud packages
-        uses: actions/cache@v3
+        uses: actions/cache@v4
         with:
           path: ~/.sonar/cache
           key: ${{ runner.os }}-sonar
           restore-keys: ${{ runner.os }}-sonar
       - name: Cache Maven packages
-        uses: actions/cache@v3
+        uses: actions/cache@v4
         with:
           path: ~/.m2
           key: ${{ runner.os }}-m2-${{ hashFiles('**/pom.xml') }}