fix: stale bot PR label (#326)

# Description

s/stale-pr-label**s**/stale-pr-label


https://github.com/actions/stale?tab=readme-ov-file#list-of-input-options

This is why PRs are being labelled with `Stale` instead of the
configured `meta/waiting-for-author` 🙁

## Related Issue

If this pull request is related to any issue, please mention it here.
Additionally, make sure that the issue is assigned to you before
submitting this pull request.

## Checklist

- [x] I have read the [contributing
documentation](https://retina.sh/docs/contributing).
- [x] I signed and signed-off the commits (`git commit -S -s ...`). See
[this
documentation](https://docs.github.com/en/authentication/managing-commit-signature-verification/about-commit-signature-verification)
on signing commits.
- [x] I have correctly attributed the author(s) of the code.
- [x] I have tested the changes locally.
- [x] I have followed the project's style guidelines.
- [x] I have updated the documentation, if necessary.
- [x] I have added tests, if applicable.

## Screenshots (if applicable) or Testing Completed

Please add any relevant screenshots or GIFs to showcase the changes
made.

## Additional Notes

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---

Please refer to the [CONTRIBUTING.md](../CONTRIBUTING.md) file for more
information on how to contribute to this project.

Signed-off-by: Evan Baker <[email protected]>

.github/workflows/stale.yaml

@@ -24,7 +24,7 @@ jobs:
           days-before-pr-stale: 30
           delete-branch: true
           stale-issue-label: "meta/waiting-for-author"
-          stale-pr-labels: "meta/waiting-for-author"
+          stale-pr-label: "meta/waiting-for-author"
           operations-per-run: 100
           stale-issue-message: "This issue will be closed in 7 days due to inactivity."
           stale-pr-message: "This PR will be closed in 7 days due to inactivity."