Upgrade CI script to use Java 11 now that it is supported.

Author: analyst

.github/workflows/maven.yaml

@@ -11,10 +11,10 @@ jobs:
     - uses: actions/checkout@v4
       with:
         fetch-depth: 0
-    - name: Set up JDK 8
+    - name: Set up JDK 11
       uses: actions/setup-java@v4
       with:
-        java-version: '8'
+        java-version: '11'
         distribution: 'zulu'
     - name: Run Spotless check
       run: mvn spotless:check