Datasette-auth-github

* Fix for bug interacting with other plugins such as [datasette-search-all](https://github.com/simonw/datasette-search-all) - #58

* Subclasses can now customize the creation of the redirect cookie - 49 - thanks, ananis25

* New `cacheable_prefixes` mechanism to avoid performance issues caused by adding `cache-control: private` to static assets - 47

- Updated documentation to reflect new one hour `cookie_ttl` default - 43

- Explicit log in screen now includes SVG GitHub logo on the button - 42
- Default signed cookie TTL is now 1 hour, not 24 hours - 43

Now compatible with Python 3.5, which means it can run on Glitch! https://datasette-auth-github-demo.glitch.me/ #38

This also means we now have no installation dependencies, since the code now uses the standard library to make API calls instead of depending on [http3](https://github.com/encode/http3). #40