Update the Hook callback to be compatible with xgboost>1.3.0 callback style

[haixiw]

from xgboost version 1.3.0 and later, all the callbacks taken by xgb.train() must be instances of xgb.callback.TrainingCallback https://xgboost.readthedocs.io/en/stable/python/python_api.html#callback-api From the usage : https://github.com/awslabs/sagemaker-debugger/blob/master/smdebug/xgboost/hook.py#L64 If we pass Hook together with other callbacks which are instances of xgb.callback.TrainingCallback, an Assert Error will happen because of the check here : https://github.com/dmlc/xgboost/blob/v1.5.2/python-package/xgboost/training.py#L62

[mabunday]

Reference: https://github.com/aws/sagemaker-xgboost-container/pull/301

[yl-to]

Issue should be fixed by PR:https://github.com/awslabs/sagemaker-debugger/pull/648 Closing.