Merge pull request #43 from iht/iht-patch-1

Update to Java 21

Author: iht

.github/workflows/gradle.yml

@@ -22,10 +22,10 @@ jobs:
 
     steps:
     - uses: actions/checkout@v5
-    - name: Set up JDK 11
+    - name: Set up JDK 21
       uses: actions/setup-java@v5
       with:
-        java-version: '11'
+        java-version: '21'
         distribution: 'temurin'
 
     # Configure Gradle for optimal use in GitHub Actions, including caching of downloaded dependencies.