Log Message:
databases/py-peewee: Update to 3.1.3.

- Fixed issue where scope-specific settings were being updated
  in-place instead of copied.
- Fixed bug where setting a ForeignKeyField did not add it to
  the model's "dirty" fields list.
- Use pre-fetched data when using prefetch() with ManyToManyField.
- Use JSON data-type for SQLite JSONField instances.
- Add a json_contains function for use with SQLite json1 extension.
- Various documentation updates and additions.