chore: add exemptions to stale workflow (#1276)

# Description
Ignores draft PRs and adds a label to preserve PRs so they don't become
stale

## Related Issue

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Additionally, make sure that the issue is assigned to you before
submitting this pull request.

## Checklist

- [ ] I have read the [contributing
documentation](https://retina.sh/docs/contributing).
- [ ] 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.
- [ ] I have correctly attributed the author(s) of the code.
- [ ] I have tested the changes locally.
- [ ] I have followed the project's style guidelines.
- [ ] I have updated the documentation, if necessary.
- [ ] I have added tests, if applicable.

## Screenshots (if applicable) or Testing Completed

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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

@@ -23,6 +23,8 @@ jobs:
           days-before-pr-close: 7
           days-before-pr-stale: 30
           delete-branch: true
+          exempt-draft-pr: true
+          exempt-pr-labels: "meta/preserve"
           stale-issue-label: "meta/waiting-for-author"
           stale-pr-label: "meta/waiting-for-author"
           operations-per-run: 100