Modify git co

.gitlab-ci.yml

@@ -15,6 +15,6 @@ build:
   stage: build
   script:
     - apk update ; apk add git
-    - git checkout master
+    - git checkout master --
     - docker build --pull -t "$CI_REGISTRY_IMAGE:testing-ubuntu" .
     - docker push "$CI_REGISTRY_IMAGE:testing-ubuntu"