Update to wagtail-factories==2.1.0

Changelog: https://github.com/wagtail/wagtail-factories/compare/2.0.1...2.1.0

2.1.0
=====
 - Add support for Wagtail 3.0 and drop support for all Wagtail versions
   before 2.15
 - Add support for Django 4.0
 - Add support for Python 3.10
 - Removed support for Python 3.6
 - Removed support for Django 2.2 and 3.1
 - Removed support for factory boy <3.2

requirements-dev.txt

@@ -7,5 +7,5 @@ isort==5.10.1
 model-bakery==1.3.3
 responses==0.16.0
 stellar==0.4.5
-wagtail-factories==2.0.1
+wagtail-factories==2.1.0
 Werkzeug==2.0.2