Update GitLab CI config

.gitlab-ci.yml

+before_script:
+  - for ip in $(dig @8.8.8.8 github.com +short); do ssh-keyscan github.com,$ip; ssh-keyscan $ip; done 2>/dev/null >> ~/.ssh/known_hosts
+  - for ip in $(dig @8.8.8.8 git.xx.network +short); do ssh-keyscan git.xx.network,$ip; ssh-keyscan $ip; done 2>/dev/null >> ~/.ssh/known_hosts
+  - xcodebuild -version
+
 stages:
   - test
 
@@ -22,7 +27,5 @@ test-examples-ios:
   tags: 
     - ios
   script:
-    - for ip in $(dig @8.8.8.8 github.com +short); do ssh-keyscan github.com,$ip; ssh-keyscan $ip; done 2>/dev/null >> ~/.ssh/known_hosts
-    - for ip in $(dig @8.8.8.8 git.xx.network +short); do ssh-keyscan git.xx.network,$ip; ssh-keyscan $ip; done 2>/dev/null >> ~/.ssh/known_hosts
     - ./run-tests.sh examples-ios
   retry: 1