retry selenium tests several times

.gitlab-ci.yml

@@ -121,7 +121,12 @@ selenium:
   extends: .integration-test
   script:
     - export K8S_NAMESPACE=$(kubectl get pods -o=custom-columns=NS:.metadata.namespace | tail -1)
-    - python3 tests/integration/selenium_test.py
+    - |
+      for i in `seq 1 3`; do
+        echo attempt $i...
+        python3 tests/integration/selenium_test.py && break
+        sleep 3
+      done
   needs:
     - job: phpunit-integration
   artifacts: