Bump mlflow from 2.2.1 to 2.5.0 in /requirements

Bumps [mlflow](https://github.com/mlflow/mlflow) from 2.2.1 to 2.5.0.
- [Release notes](https://github.com/mlflow/mlflow/releases)
- [Changelog](https://github.com/mlflow/mlflow/blob/master/CHANGELOG.md)
- [Commits](mlflow/mlflow@v2.2.1...v2.5.0)

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

Signed-off-by: dependabot[bot] <support@github.com>

requirements/optional.txt

@@ -3,7 +3,7 @@ ConfigSpace
 flaml==1.0.14
 hpbandster
 hyperopt==0.2.5
-mlflow==2.2.1
+mlflow==2.5.0
 nevergrad==0.4.3.post7
 optuna==2.10.0
 scikit-learn