Update .gitlab-ci.yml file

.gitlab-ci.yml

@@ -20,5 +20,5 @@ build:
       --tag $CI_REGISTRY_IMAGE:$CI_COMMIT_SHORT_SHA --tag $CI_REGISTRY_IMAGE:latest .
       ; fi
     - docker push $CI_REGISTRY_IMAGE:$CI_COMMIT_SHORT_SHA
-    - docker push $CI_REGISTRY_IMAGE:latest
+    - if [ $CI_COMMIT_BRANCH == 'master' ] ;then docker push $CI_REGISTRY_IMAGE:latest ;fi
     - if [ $CI_COMMIT_TAG != '' ]; then docker push $CI_REGISTRY_IMAGE:$CI_COMMIT_TAG ;fi