Make linter output visible

.gitlab-ci.yml

@@ -27,7 +27,7 @@ eslint:
   script:
     - npm install
     # eslint exits 0 on warnings, this is a workaround to exit 1 when warnings are present.
-    - "! npm run lint | grep -qE '✖ [0-9]+ problem'"
+    - "! npm run lint | tee /dev/tty | grep -qE '✖ [0-9]+ problem'"
   allow_failure: true
   needs: []