infra: bump aws-actions/stale-issue-cleanup from 3 to 6

Bumps [aws-actions/stale-issue-cleanup](https://github.com/aws-actions/stale-issue-cleanup) from 3 to 6.
- [Release notes](https://github.com/aws-actions/stale-issue-cleanup/releases)
- [Commits](aws-actions/stale-issue-cleanup@v3...v6)

---
updated-dependencies:
- dependency-name: aws-actions/stale-issue-cleanup
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

.github/workflows/stale_issue.yml

@@ -11,7 +11,7 @@ jobs:
     runs-on: ubuntu-latest
     name: Stale issue job
     steps:
-      - uses: aws-actions/stale-issue-cleanup@v3
+      - uses: aws-actions/stale-issue-cleanup@v6
         with:
           # Setting messages to an empty string will cause the automation to skip
           # that category