Upgrade Python to 3.8.2 and Django to 3.0.7

.python-version

@@ -1 +1 @@
-3.6.8
+3.8.2

config/requirements_core.txt

@@ -1,20 +1,18 @@
 # The necessary dependencies to run Tabbycat
 
 # Django
-Django==2.2.13
+Django==3.0.7
 django-appconf==1.0.3                   # Helper for handling app configs
-django-dynamic-preferences==1.7.1       # Settings management
-django-extensions==2.2.1                # For the generate secret command
-django-formtools==2.1                   # Form wizards
+django-dynamic-preferences==1.9         # Settings management
+django-extensions==2.2.9                # For the generate secret command
+django-formtools==2.2                   # Form wizards
 django-ipware==2.1.0                    # IP Address logging
-django-jet==1.0.8                       # Admin Backend
-django-gfklookupwidget==1.0.7           # Replaces object_id field with a search link
-djangorestframework==3.10.2             # For serialising objects
+django-gfklookupwidget==1.0.8           # Replaces object_id field with a search link
+djangorestframework==3.11.0             # For serialising objects
 django-polymorphic==2.1.2               # Permits model polymorphism
 django-split-settings==1.0.0            # Modularise settings files
 django-statici18n==1.8.3                # Compile translations files as static file
-django-summernote==0.8.11.4             # WYSIWYG editor
-munkres==1.1.2                          # Algorithm for adjudicator allocation
+django-summernote==0.8.11.6             # WYSIWYG editor
 dj-cmd==1.0                             # Provides the dj command alias
 
 # Database
@@ -30,7 +28,13 @@ channels==2.2.0                         # Channels; also includes the Daphne ser
 channels_redis==2.4.2                   # Channels Layer
 
 # Misc
-ipython==7.11.*
+ipython==7.15.*
+munkres==1.1.2                          # Algorithm for adjudicator allocation
 redis==3.3.8
 qrcode==6.1                             # QR codes for printed private URL sheets
 html2text==2019.8.11                    # Compatibility with plain-text email clients
+
+# Django admin (Jet)
+# This is an unofficial fork of no-longer-maintained geex-arts/django-jet,
+# patched to support Django 3.
+r-django-jet==2.0.8

config/requirements_heroku.txt

@@ -9,7 +9,7 @@ honcho==1.0.1                           # Allows a Procfile to run multiple proc
 gunicorn==19.9.0                        # Primary server for wsgi
 
 # Cache
-django-redis==4.10.0                    # Use redis for cache (on heroku; local optional)
+django-redis==4.12.1                    # Use redis for cache (on heroku; local optional)
 
 # Misc
 sendgrid==6.0.5                         # Email service of choice on Heroku

tabbycat/participants/models.py

@@ -182,7 +182,7 @@ class Team(models.Model):
     type = models.CharField(max_length=1, choices=TYPE_CHOICES, default=TYPE_NONE,
         verbose_name=_("type"))
 
-    emoji = models.CharField(max_length=2, default=None, choices=EMOJI_FIELD_CHOICES,
+    emoji = models.CharField(max_length=3, default=None, choices=EMOJI_FIELD_CHOICES,
         blank=True, null=True,   # uses null=True to allow multiple teams to have no emoji
         verbose_name=_("emoji"))