chore: scope the stale_issue.yaml workflow to run only on this repository

Author: ianbotsf

.github/workflows/stale_issue.yaml

@@ -12,6 +12,7 @@ jobs:
   cleanup:
     name: Stale issue job
     runs-on: ubuntu-latest
+    if: github.repository == 'aws/aws-sdk-kotlin'
     steps:
     - uses: aws-actions/stale-issue-cleanup@v4
       with: