transformers

766d4bf7 - Fix MLflowCallback end_run() and add support for tags and nested runs (#17130)

Fix MLflowCallback end_run() and add support for tags and nested runs (#17130) * ensure mlflow.end_run() is executed at end of training when mlflow.start_run() was executed by the callback * add debug msg * add support for MLFLOW_TAGS, MLFLOW_RUN_ID, and MLFLOW_NESTED_RUN * update to support python 3.6+ * Validate env variables using ENV_VARS_TRUE_VALUES * Empty-Commit