MINOR: mux-h2: add trace on extended connect usage

Add a state trace to report that a protocol upgrade is converted using
the rfc8441 Extended connect method. This is useful in regards with the
recent changes to improve http/2 websockets.

(cherry picked from commit e0c258c84d57765c50a3e9e5a243f954474462f7)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
1 file changed