Run Build only on main branch

.gitlab-ci.yml

@@ -35,3 +35,5 @@ Build Docker Image 📦:
     - docker build -t $DOCKER_IMAGE:$CURRENT_TAG -t $DOCKER_IMAGE:latest alma9-base
     - docker login -u $CI_REGISTRY_USER -p $CI_REGISTRY_PASSWORD
     - docker push cverstege/alma9-base --all-tags
+  only:
+    - main