Update Java version to 21 in release workflow

Author: devkanro

.github/workflows/release.yml

@@ -29,7 +29,7 @@ jobs:
         uses: actions/setup-java@v4
         with:
           distribution: zulu
-          java-version: 17
+          java-version: 21
 
       # Setup Gradle
       - name: Setup Gradle
@@ -98,4 +98,4 @@ jobs:
             --title "Changelog update - \`$VERSION\`" \
             --body "Current pull request contains patched \`CHANGELOG.md\` file for the \`$VERSION\` version." \
             --label "$LABEL" \
-            --head $BRANCH
+            --head $BRANCH