fix swappable dependency

Author: n2ygk

oauth2_provider/migrations/0012_add_token_checksum.py

@@ -2,12 +2,12 @@
 
 import oauth2_provider.models
 from django.db import migrations, models
-
+from oauth2_provider.settings import oauth2_settings
 
 class Migration(migrations.Migration):
     dependencies = [
         ("oauth2_provider", "0011_refreshtoken_token_family"),
-        migrations.swappable_dependency(settings.OAUTH2_PROVIDER_ACCESS_TOKEN_MODEL),
+        migrations.swappable_dependency(oauth2_settings.OAUTH2_PROVIDER_ACCESS_TOKEN_MODEL),
     ]
 
     operations = [