Update ci.yml

Author: riccardobl

.github/workflows/ci.yml

@@ -47,7 +47,7 @@ jobs:
         uses: actions/setup-java@v4
         with:
           distribution: temurin
-          java-version: "8"
+          java-version: "21"
           cache: gradle
 
       - name: Resolve release version (from release name)
@@ -73,4 +73,4 @@ jobs:
           ./gradlew --no-daemon \
             -PreleaseVersion='${{ steps.ver.outputs.releaseVersion }}' \
             clean build \
-            publishMavenJavaPublicationToGitHubPackagesRepository
+            publishMavenJavaPublicationToGitHubPackagesRepository