SERVER_PROTOCOL format is not correct

[Libing Chen]

Now value of SERVER_PROTOCOL is http or https, but from https://datatracker.ietf.org/doc/html/rfc3875 the SERVER_PROTOCOL should be alike HTTP-Version = "HTTP" "/" 1*digit "." 1*digit, such as HTTP/1.1 .

[Matt Butcher]

Looks like it was fetching protocol from the URL instead of version from the request object. I will fix.

[Radu Matei]

Fixed in #112.