[3.2.x] Added CVE-2021-44420 to security archive.

Backport of 8747052 from main

docs/releases/security.txt

@@ -36,6 +36,20 @@ Issues under Django's security process
 All security issues have been handled under versions of Django's security
 process. These are listed below.
 
+December 7, 2021 - :cve:`2021-44420`
+------------------------------------
+
+Potential bypass of an upstream access control based on URL paths. `Full
+description
+<https://www.djangoproject.com/weblog/2021/dec/07/security-releases/>`__
+
+Versions affected
+~~~~~~~~~~~~~~~~~
+
+* Django 3.2 :commit:`(patch) <333c65603032c377e682cdbd7388657a5463a05a>`
+* Django 3.1 :commit:`(patch) <22bd17488159601bf0741b70ae7932bffea8eced>`
+* Django 2.2 :commit:`(patch) <7cf7d74e8a754446eeb85cacf2fef1247e0cb6d7>`
+
 July 1, 2021 - :cve:`2021-35042`
 --------------------------------