import { parseHTTPVersion } from "https://deno.land/x/deno@v0.28.0/std/http/mod.ts";
ParseHTTPVersion parses a HTTP version string. "HTTP/1.0" returns (1, 0, true). Ported from https://github.com/golang/go/blob/f5c43b9/src/net/http/request.go#L766-L792