Update jdk used in actions

.github/workflows/gradle.yml

@@ -11,11 +11,11 @@ jobs:
       uses: actions/checkout@v4
     - name: Validate Gradle Wrapper
       uses: gradle/wrapper-validation-action@v2
-    - name: Set up JDK 17
+    - name: Set up JDK 21
       uses: actions/setup-java@v4
       with:
         distribution: 'temurin'
-        java-version: 17
+        java-version: 21
         check-latest: true
     - name: Build and test with Gradle
       run: ./gradlew test

.github/workflows/main.yml

@@ -24,7 +24,7 @@ jobs:
         uses: actions/setup-java@v4
         with:
           distribution: 'temurin'
-          java-version: 17
+          java-version: 21
           check-latest: true
 
       - name: Validate Gradle Wrapper