drop python 3.6 support

python 3.6 reached end of life on 2021-12-23

pre_commit/meta_hooks/identity.py

@@ -1,11 +1,12 @@
+from __future__ import annotations
+
 import sys
-from typing import Optional
 from typing import Sequence
 
 from pre_commit import output
 
 
-def main(argv: Optional[Sequence[str]] = None) -> int:
+def main(argv: Sequence[str] | None = None) -> int:
     argv = argv if argv is not None else sys.argv[1:]
     for arg in argv:
         output.write_line(arg)