Added "Bugfixes" section to release notes for 3.1.2.

docs/releases/3.1.2.txt

@@ -2,6 +2,11 @@
 Django 3.1.2 release notes
 ==========================
 
-*October 1, 2020*
+*Expected October 1, 2020*
 
 Django 3.1.2 fixes several bugs in 3.1.1.
+
+Bugfixes
+========
+
+* ...