fix #983. -- colllections.abc import for Python 3.10

Author: dimitri-yatsenko

datajoint/external.py

@@ -1,5 +1,5 @@
 from pathlib import Path, PurePosixPath, PureWindowsPath
-from collections import Mapping
+from collections.abc import Mapping
 from tqdm import tqdm
 from .settings import config
 from .errors import DataJointError, MissingExternalFile

datajoint/settings.py

@@ -58,7 +58,7 @@
 }
 
 
-class Config(collections.MutableMapping):
+class Config(collections.abc.MutableMapping):
 
     instance = None