java 21 in github stuffs

.github/workflows/devbuild.yml

@@ -12,11 +12,11 @@ jobs:
 
     steps:
     - uses: actions/checkout@v3
-    - name: Set up JDK 17
+    - name: Set up JDK 21
       uses: actions/setup-java@v3
       with:
         distribution: 'temurin'
-        java-version: 17
+        java-version: 21
         cache: 'gradle'
     - name: Grant execute permission to gradlew
       run: chmod +x gradlew