Make random 'state' for github authorization, really random.

There is `state` option in authorization to Github, which should be "An unguessable random string. It is used to protect against cross-site request forgery attacks.". Right now, it is just hardcoded string, so it definitelly doesnt give much protection.

See below:
https://docs.github.com/en/free-pro-team@latest/developers/apps/authorizing-oauth-apps#web-application-flow