Use Java 21 when generating the coverage.

.github/workflows/coverage.yml

@@ -1,4 +1,4 @@
-name: 'Generate coverage report'
+name: 'CodeCov'
 
 on:
   push:
@@ -11,20 +11,25 @@ jobs:
   coverage:
 
     runs-on: ubuntu-latest
-    name: Coverage on Ubuntu
+    name: Create and upload coverage report
 
     steps:
       - uses: actions/checkout@v4
-      - name: Set up JDK 11
+      - name: Set up JDK 21
         uses: actions/setup-java@v4
         with:
           distribution: 'temurin'
-          java-version: '11'
+          java-version: '21'
           check-latest: true
+          cache: 'maven'
+      - name: Set up Maven
+        uses: stCarolas/setup-maven@v4.5
+        with:
+          maven-version: 3.9.6
       - name: Generate coverage with JaCoCo
-        run: mvn -V --color always -ntp clean verify --file pom.xml '-Dgpg.skip'
+        run: mvn -V --color always -ntp clean verify '-Dgpg.skip'
       - name: Upload coverage to Codecov
-        uses: codecov/codecov-action@v3
+        uses: codecov/codecov-action@v3.1.4
         with:
           files: 'target/site/jacoco/jacoco.xml'
           token: ${{secrets.CODECOV_TOKEN}}