Update gradle.yml

Author: Andcool-Systems

.github/workflows/gradle.yml

@@ -16,11 +16,11 @@ jobs:
       - name: Checkout repository
         uses: actions/checkout@v4
 
-      - name: Set up JDK 17
+      - name: Set up JDK 21
         uses: actions/setup-java@v4
         with:
           distribution: 'adopt'
-          java-version: '17'
+          java-version: '21'
 
       - name: Cache Gradle packages
         uses: actions/cache@v4