Switch PR build to Java 21

Author: coheigea

.github/workflows/pull-request-build.yaml

@@ -8,36 +8,18 @@ permissions:
   contents: read
 
 jobs:
-  build-java-8:
+  build-java-21:
     runs-on: ubuntu-latest
     permissions:
       contents: read  
       pull-requests: read
     timeout-minutes: 130
     steps:
       - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
-      - name: Set up JDK 8
+      - name: Set up JDK 21
         uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5.2.0
         with:
-          java-version: '8'
-          distribution: 'temurin'
-          cache: maven
-      - name: Build with Apache Maven
-        run: mvn -U clean install -Djava.awt.headless=true -fae -B
-    env: 
-       MAVEN_OPTS: "-Xmx1024M"
-  build-java-17:
-    runs-on: ubuntu-latest
-    permissions:
-      contents: read  
-      pull-requests: read
-    timeout-minutes: 130
-    steps:
-      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
-      - name: Set up JDK 17
-        uses: actions/setup-java@be666c2fcd27ec809703dec50e508c2fdc7f6654 # v5.2.0
-        with:
-          java-version: '17'
+          java-version: '21'
           distribution: 'temurin'
           cache: maven
       - name: Build with Apache Maven