Rasa-sdk

No significant changes.

Improvements
- [261](https://github.com/rasahq/rasa/issues/261): Adding support for forms with the `required_slots` key which is introduced as part of Rasa Open Source 2.6.
- [434](https://github.com/rasahq/rasa/issues/434): - The action server can now listen on a specific network address using the environment variable `SANIC_HOST` instead of listening on all host interfaces by default
- Corrected url which is logged at action server startup

Miscellaneous internal changes
- [376](https://github.com/rasahq/rasa/issues/376)

Bugfixes
- [419](https://github.com/rasahq/rasa/issues/419): Missing `typing_extensions` module added

Minor dependency updates
- [8223](https://github.com/rasahq/rasa/issues/8223): `utter_message` in `CollectingDispatcher` now explicitly takes in both `response` and `template`. Note that the parameter `template` will be deprecated in Rasa SDK 3.0.0. Please use `dispatcher.utter_message(response=...)` instead.

Bugfixes
- [406](https://github.com/rasahq/rasa/issues/406): Fix bug where ActionQueryKnowledgeBase incorrectly issues a template message with the string representation of the function for getting the string representation of the knowledge base item and not the actual string representation of the knowledge base item.

For example, before the fix, the query knowledge base demo bot would utter this


'<function ActionMyKB.init.. at 0x7fb23b7fddd0>' has the value 'True' for attribute 'breakfast-included'.


instead of this:


'Hilton (Berlin)' has the value 'True' for attribute 'breakfast-included'.

Bugfixes
- [404](https://github.com/rasahq/rasa/issues/1234): Only pin the `uvloop` dependency for non-Windows systems as `uvloop` is not available
for Windows.