[1.4.x] Added information on resolved security issues to release notes.
[1.4.x] Added information on resolved security issues to release notes.

Backport of c07f3e60c2d455e36ba4ac339d4283d32bbc3814 from master

riklaunim/django-custom-multisite,riklaunim/django-custom-multisite,riklaunim/django-custom-multisite