logger: Remove deprecation warning reported by pytest
logger: Remove deprecation warning reported by pytest

dvc/logger.py:113: DeprecationWarning: The 'warn' method is deprecated, use 'warning' instead

dataversioncontrol/dvc,efiop/dvc,dmpetrov/dataversioncontrol,dmpetrov/dataversioncontrol,efiop/dvc,dataversioncontrol/dvc