Datasette-auth-github

* New `require_auth` configuration option. This defaults to `True` (reflecting existing behaviour) when `datasette-auth-github` is used as a Datasette plugin, but it defaults to `False` if you use the wrapper ASGI middleware class directly. 37

Additional documentation on `scope["auth"]` when using as ASGI middleware.

Updated README for PyPI

Minor code clean-up and updated one-line description for PyPI / README.

* Redirects back to where you were after you login, using a new `asgi_auth_redirect` cookie - 26
* Unset asgi_auth_logout cookie when you sign in again - 28
* Fixed bug where API call to GitHub intermittently failed with `ConnectionResetError` - 27
* More robust creation of derived cookie signing secret using `hashlib.pbkdf2_hmac`
* HTML pages now served with `charset=UTF-8` - 30

* New `allow_teams` configuration option for restricting access to members of a GitHub team - 11
* Signed cookies expire after a TTL (customize with new `cooke_ttl` setting) - 22
* Documentation on using this as ASGI middleware - 19
* Avoid 404 on `/-/auth-callback` if user is logged in - 24
* Added `cookie_version` setting for invalidating all cookies - 18