doc: update readthedocs requirement file

Author: fallen

readthedocs_requirements.txt

@@ -1,11 +1,13 @@
-Django~=2.2.0
-django-colorfield==0.1.15
-django-tinymce==2.8.0
-django-mailer==1.2.6
+Django~=4.2.0
+django-colorfield==0.10.1
+django-tinymce==3.6.1
+django-mailer==2.3
+django-maintenance-mode
+django-phonenumber-field[phonenumbers]==6.3.0
 requests~=2.20.0
 django-widget-tweaks==1.4.3
 beautifulsoup4~=4.6.3
-django-formtools==2.1
+django-formtools==2.2
 bcrypt
 lxml
 uwsgi