Added YugabyteDB to list of third-party DB backends.

docs/ref/databases.txt

@@ -1118,6 +1118,7 @@ by 3rd parties that allow you to use other databases with Django:
 * `Google Cloud Spanner`_
 * `Microsoft SQL Server`_
 * `TiDB`_
+* `YugabyteDB`_
 
 The Django versions and ORM features supported by these unofficial backends
 vary considerably. Queries regarding the specific capabilities of these
@@ -1129,3 +1130,4 @@ the support channels provided by each 3rd party project.
 .. _Google Cloud Spanner: https://pypi.org/project/django-google-spanner/
 .. _Microsoft SQL Server: https://pypi.org/project/mssql-django/
 .. _TiDB: https://pypi.org/project/django-tidb/
+.. _YugabyteDB: https://pypi.org/project/django-yugabytedb/