github/submodule-update: Ensure exit 0 on the update check

I *think* the `exit 0` is to ensure the 'Check for changes' isn't considered
failed due to `git` exit code.

.github/workflows/submodule-update.yml

@@ -39,8 +39,8 @@ jobs:
             echo '::set-output changes=true'
           else
             echo '::set-output changes=false'
-            exit 0
           fi
+          exit 0
       
       - name: Create submodules changes branch
         if: steps.check_for_changes.outputs.changes == 'true'