Force HTTP1.1 Only

[riramar]

Please describe your feature request:

Add a flag to force HTTP1.1 only like --http1.1 on curl.

Describe the use case of this feature:

If the user wants to probe using HEAD method to speed up the process and filter/match responses by the Content-Length response header the tool must use HTTP1 because HTTP2 do not provides Content-Length response header.