style: pre-commit.ci auto fixes [...]

Author: pre-commit-ci[bot]

src/taskgraph/transforms/base.py

@@ -2,7 +2,6 @@
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
-import asyncio
 import inspect
 import re
 from dataclasses import dataclass, field