Update xgboost requirement in /docker/openproblems-python-extras

Updates the requirements on [xgboost](https://github.com/dmlc/xgboost) to permit the latest version.
- [Release notes](https://github.com/dmlc/xgboost/releases)
- [Changelog](https://github.com/dmlc/xgboost/blob/master/NEWS.md)
- [Commits](dmlc/xgboost@v1.6.0rc1...v1.7.3)

---
updated-dependencies:
- dependency-name: xgboost
  dependency-type: direct:production
...

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

Author: dependabot[bot]

docker/openproblems-python-extras/requirements.txt

@@ -4,4 +4,4 @@ git+https://github.com/KrishnaswamyLab/[email protected]#subdirectory=pyth
 git+https://github.com/scottgigante-immunai/knn-smoothing@python_package
 magic-impute==3.0.*
 phate==1.0.*
-xgboost==1.6.*
+xgboost==1.7.*