CI: add "no-op" job

Author: Philippe-Cholet

.github/workflows/ci.yml

@@ -9,6 +9,8 @@ on:
       - "**.md"
 
 jobs:
+  no-op:
+
   check:
     runs-on: ubuntu-latest
     strategy:
@@ -79,7 +81,7 @@ jobs:
     name: All checks succeeded
     if: success()
     runs-on: ubuntu-latest
-    needs: [check, msrv, test, check-format, doc]
+    needs: [no-op, check, msrv, test, check-format, doc]
     steps:
       - name: Mark the job as successful
         run: exit 0