Update to Django 3.0

Update django extensions and django itself to 3.0.6.
Signed-off-by: Jelle van der Waa <jelle@archlinux.org>

requirements.txt

 -e git+git://github.com/fredj/cssmin.git@master#egg=cssmin
-Django==2.2.11
+Django==3.0.5
 IPy==1.00
 Markdown==3.2.1
 bencode.py==2.0.0
 django-countries==5.5
-django-extensions==2.2.1
+django-extensions==2.2.8
 jsmin==2.2.2
 pgpdump==1.5
 pytz>=2019.2
 parse==1.14.0
 django-jinja==2.6.0
 sqlparse==0.3.0
-django-csp==3.5
+django-csp==3.6
 ptpython==2.0.4
 feedparser==5.2.1
 bleach==3.1.4