CI: dynamically determine actual version of h2spec

previously we used hardcoded h2spec version. let us switch to
the latest available

(cherry picked from commit 0a802114e098757be0fa61d6f119f6ee00440254)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
(cherry picked from commit 4f10f6e2bb1b23f037e3849d49aa53a8a3663dd8)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
1 file changed