[3.10] bpo-44559: [Enum] revert enum module to 3.9 (GH-27010)

* [Enum] revert enum module to 3.9
diff --git a/Lib/plistlib.py b/Lib/plistlib.py
index 5772efd..2eeebe4 100644
--- a/Lib/plistlib.py
+++ b/Lib/plistlib.py
@@ -61,7 +61,8 @@
 from xml.parsers.expat import ParserCreate
 
 
-PlistFormat = enum.global_enum(enum.Enum('PlistFormat', 'FMT_XML FMT_BINARY', module=__name__))
+PlistFormat = enum.Enum('PlistFormat', 'FMT_XML FMT_BINARY', module=__name__)
+globals().update(PlistFormat.__members__)
 
 
 class UID: