fix CI: remove $CI_REGISTRY

.gitlab-ci.yml

@@ -38,7 +38,7 @@ build:
 
 upload:review:
   stage: upload
-  image: $CI_REGISTRY/alpine:latest
+  image: alpine:latest
   environment:
     name: review/$CI_COMMIT_REF_NAME
     on_stop: stop:review
@@ -55,7 +55,7 @@ upload:review:
 
 upload:production:
   stage: upload
-  image: $CI_REGISTRY/alpine:latest
+  image: alpine:latest
   environment:
     name: production
     url: https://docs.fitko.de/fit-connect/
@@ -70,7 +70,7 @@ upload:production:
 
 stop:review:
   stage: .post
-  image: $CI_REGISTRY/alpine:latest
+  image: alpine:latest
   environment:
     name: review/$CI_COMMIT_REF_NAME
     action: stop