Added

• Document how to assert that no requests were issued.
• Document how to send cookies.
• Explicit support for python 3.9

Changed

• Requires httpx==0.16.*
• Update documentation to reflect the latest way of sending bytes using httpx. Via content parameter instead of data.
• Code now follow black==20.8b1 formatting instead of the git master version.
• Sending a JSON response using json parameter will now set the application/json content-type header by default.

Fixed

• Allow to provide any supported httpx headers type in headers parameter for httpx_mock.add_response and pytest_httpx.to_response. Previously only dict was supported.