Update MLFlow version (openvinotoolkit#2291)

### Changes

- As stated in the title.

### Related tickets

- 125654

examples/torch/requirements.txt

@@ -3,7 +3,7 @@ pillow>=8.0.1
 tensorboard>=2.1
 matplotlib>=3.3.3
 defusedxml>=0.7.0rc1
-mlflow>=2.5.0,<2.7.0
+mlflow==2.8.1
 returns>0.14
 opencv-python>=4.4.0.46
 torchvision>=0.10.0,<0.17  # the minor version should always match the torch minor version that is installed via NNCF's `pip install nncf[torch]`; TV minor version is torch minor version +1