The default is to now to not clear the `Accept-Encoding` header (this can be changed back to the older behavior by passing `reset_accept_encoding: true`)
Although the HTTP Version appears as a header inside `env`, it's not actually a regular header. When `extract_http_request_headers` is called, it translates the `HTTP_VERSION` "header" into a `Version` header. `Version` is only a provisionally-supported header name, and is semantically meant to represent the version of an (evolving object)[https://www.w3.org/Protocols/HTTP/Object_Headers.html#z13]. It's not correct to pass the HTTP Version as the contents of the `Version` header, so this change skips the processing of that particular header entirely.