build(ci): add version option to graalvm setup step

- Specify 'latest' version for GraalVM21.x setup
- This change ensures the latest available version of GraalVM 21 is used in CI builds

.github/workflows/gradle-build.yml

@@ -28,6 +28,7 @@ jobs:
       - name: Set up graalvm 21 for x64
         uses: graalvm/setup-graalvm@v1
         with:
+          version: 'latest'
           java-version: '21'
           distribution: 'liberica'
           native-image-job-reports: 'true'