import generic abstract collections from typing module, instead of co…

…llections.abc

Fixes TypeError on Python 3.8
https://github.com/fonttools/ufoLib2/actions/runs/3404749253/jobs/5662213808

src/ufoLib2/objects/contour.py

@@ -1,8 +1,7 @@
 from __future__ import annotations
 
 import warnings
-from collections.abc import MutableSequence
-from typing import Iterable, Iterator, List, Optional, overload
+from typing import Iterable, Iterator, List, MutableSequence, Optional, overload
 
 from attrs import define, field
 from fontTools.pens.basePen import AbstractPen

src/ufoLib2/objects/image.py

@@ -1,7 +1,6 @@
 from __future__ import annotations
 
-from collections.abc import Mapping
-from typing import Any, ClassVar, Iterator, Optional, Tuple
+from typing import Any, ClassVar, Iterator, Mapping, Optional, Tuple
 
 from attrs import define, field
 from fontTools.misc.transform import Identity, Transform

src/ufoLib2/objects/misc.py

@@ -1,16 +1,16 @@
 from __future__ import annotations
 
-import collections.abc
 import uuid
 from abc import abstractmethod
-from collections.abc import Mapping, MutableMapping
 from copy import deepcopy
 from functools import lru_cache
 from typing import (
     TYPE_CHECKING,
     Any,
     Dict,
     Iterator,
+    Mapping,
+    MutableMapping,
     NamedTuple,
     Optional,
     Sequence,
@@ -121,7 +121,7 @@ def _object_lib(parent_lib: dict[str, Any], obj: HasIdentifier) -> dict[str, Any
         object_libs = parent_lib["public.objectLibs"] = {}
     else:
         object_libs = parent_lib["public.objectLibs"]
-        assert isinstance(object_libs, collections.abc.MutableMapping)
+        assert isinstance(object_libs, MutableMapping)
 
     if obj.identifier in object_libs:
         object_lib: dict[str, Any] = object_libs[obj.identifier]