Bump xgboost from 1.6.0 to 1.6.1 (#2921)

Bumps [xgboost](https://github.com/dmlc/xgboost) from 1.6.0 to 1.6.1.
- [Release notes](https://github.com/dmlc/xgboost/releases)
- [Changelog](https://github.com/dmlc/xgboost/blob/master/NEWS.md)
- [Commits](https://github.com/dmlc/xgboost/compare/v1.6.0...v1.6.1)

---
updated-dependencies:
- dependency-name: xgboost
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

requirements.txt

@@ -29,5 +29,5 @@ tabulate==0.8.9
 taskcluster==44.13.0
 tenacity==8.0.1
 tqdm==4.64.0
-xgboost==1.6.0
+xgboost==1.6.1
 zstandard==0.17.0