Move _value2member_map_ changelog back to 2.12.11 (#1874)

Partially reverts 4acf578.
This had been included in 2.12.11 all along.

ChangeLog

@@ -21,10 +21,6 @@ What's New in astroid 2.12.13?
 ==============================
 Release date: TBA
 
-* Add ``_value2member_map_`` member to the ``enum`` brain.
-
-  Refs PyCQA/pylint#3941
-
 * Prevent returning an empty list for ``ClassDef.slots()`` when the mro list contains one class & it is not ``object``.
 
   Refs PyCQA/pylint#5099
@@ -64,6 +60,10 @@ What's New in astroid 2.12.11?
 ==============================
 Release date: 2022-10-10
 
+* Add ``_value2member_map_`` member to the ``enum`` brain.
+
+  Refs PyCQA/pylint#3941
+
 * Improve detection of namespace packages for the modules with ``__spec__`` set to None.
 
   Closes PyCQA/pylint#7488.