fix: restore checkout in plan workflow

.gitea/workflows/terraform-plan.yml

@@ -16,9 +16,8 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      # NOTE: Gitea runners already provide the workspace checkout.
-      # Avoid actions/checkout to skip its post-job hook, which is causing
-      # false failures at the "Complete job" phase on this runner.
+      - name: Checkout repository
+        uses: actions/checkout@v3
 
       - name: Create secrets.tfvars
         working-directory: terraform