Fix ci

.gitlab-ci.yml

@@ -17,6 +17,7 @@ variables:
 
 stages:
     - build
+    - format
     - test
 
 build:
@@ -37,7 +38,7 @@ build:
 
 format:
     <<: *global_tag_def
-    stage: build
+    stage: format
     script:
         - clang-format --version # we use clang-format-10 exclusively
         - ./ext/amfe/scripts/format_code.py