fix: exit 1 on error

tests/integration-tests/ExtraArtifactsAreIncluded.gitlab-ci.yml

@@ -35,5 +35,5 @@ verify:plan-job:uploaded-extra-artifact:
         exit 0
       else
         echo 'Error: the extra artifact was not uploaded by the plan job.'
-        exit 0
+        exit 1
       fi