Update ci.yml

Author: erezrokah

.github/workflows/ci.yml

@@ -20,7 +20,7 @@ jobs:
       - uses: actions/setup-java@v5
         with:
           distribution: "temurin"
-          java-version: "18"
+          java-version: "21"
           cache: "gradle"
       - # Required for the package command tests to work
         name: Set up Docker Buildx