Update .gitlab-ci.yml file

Fixed typo

.gitlab-ci.yml

@@ -13,7 +13,7 @@ test_for_changes:
   stage: .pre
   image: ubuntu:latest
   rules:
-    -if: $CI_COMMIT_TAG
+    - if: $CI_COMMIT_TAG
   script:
     - apt update -y && apt install -y git
     # Getting current and previous tags