remove typing_extensions from install_requires

No longer needed since we target >= 3.8 now

setup.cfg

@@ -24,7 +24,6 @@ python_requires = >=3.8
 install_requires =
     attrs >= 22.1.0
     fonttools[ufo] >= 4.0.0
-    typing_extensions ; python_version < "3.8"
 
 # https://www.python.org/dev/peps/pep-0561
 [options.package_data]

src/ufoLib2/typing.py

@@ -1,18 +1,11 @@
 from __future__ import annotations
 
 import os
-import sys
-from typing import TypeVar, Union
+from typing import Protocol, TypeVar, Union
 
 from fontTools.pens.basePen import AbstractPen
 from fontTools.pens.pointPen import AbstractPointPen
 
-if sys.version_info >= (3, 8):
-    from typing import Protocol
-else:
-    from typing_extensions import Protocol
-
-
 T = TypeVar("T")
 """Generic variable for mypy for trivial generic function signatures."""