Update Gradle version to 8.7 in Vaas Java SDK example build

.github/workflows/ci.yaml

@@ -111,6 +111,7 @@ jobs:
           curl -s "https://get.sdkman.io" | bash
           source "$HOME/.sdkman/bin/sdkman-init.sh"
           sdk install gradle 8.7
+          gradle --version
           cd ./java/examples/VaasExample/
           export SCAN_PATH=$(pwd)/build.gradle
           export CLIENT_ID=vaas