Upgrade to Wagtail 2.11

requirements/base.txt

@@ -1,5 +1,4 @@
 Django>=3.1,<3.2
 django-dotenv==1.4.1
-wagtail>=2.10,<2.11
+wagtail>=2.11,<2.12
 wagtailfontawesome>=1.1.3,<1.2
-Pillow>=6.2.0,<6.3