Do a pipenv update to get patched Django

I was throwing 400s when bad parameters are provided, but the spec
actually says you're supposed to just ignore them entirely.

lemoncurry/settings/test.py

@@ -3,3 +3,6 @@ from .base import *
 ALLOWED_HOSTS = ['*']
 SECURE_SSL_REDIRECT = False
 STATICFILES_STORAGE = 'django.contrib.staticfiles.storage.StaticFilesStorage'
+
+MEDIA_URL = '/media/'
+STATIC_ROOT = path.join(BASE_DIR, 'media')

users/views.py

@@ -21,9 +21,9 @@ def libravatar(request, hash):
     try:
         size = int(size)
     except ValueError:
-        return utils.bad_req('size parameter must be an integer')
+        size = 80
     if not 1 <= size <= 512:
-        return utils.bad_req('size parameter must be between 1 and 512')
+        size = 512
 
     if len(hash) == 32:
         where = Q(email_md5=hash)