fixed wrong branch-rule

Closes #1 (closed)

.gitlab-ci.yml

@@ -6,13 +6,13 @@ build-image:
     IMAGE_NAME: "os-sweb-buildimage"
     IMAGE_TAG: $CI_REGISTRY_IMAGE/$IMAGE_NAME:latest
   services:
-      - docker:20.10.10-dind
+    - docker:20.10.10-dind
   script:
-      - docker login -u $CI_REGISTRY_USER -p $CI_REGISTRY_PASSWORD $CI_REGISTRY
-      - docker build -t $IMAGE_TAG .
-      - docker push $IMAGE_TAG 
+    - docker login -u $CI_REGISTRY_USER -p $CI_REGISTRY_PASSWORD $CI_REGISTRY
+    - docker build -t $IMAGE_TAG .
+    - docker push $IMAGE_TAG
   rules:
     - if: $CI_COMMIT_BRANCH == "main"
-    - changes:
+      changes:
         - Dockerfile
-        - .gitlab-ci.yml
\ No newline at end of file
+        - .gitlab-ci.yml