fix deployment yml in kubectl apply

.gitlab-ci.yml

@@ -49,6 +49,6 @@ Deploy to Kubernetes:
     - kubectl version
     - cd k8s
     - sed -i "s|##IMAGETAG##|${CI_COMMIT_REF_NAME}|" deployment.yaml
-    - kubectl apply -f deployment.yaml
+    - kubectl apply -f deployment.yml
   only:
     - tags