send-email: pass smtp hostname and port to Authen::SASL

Starting from version 2.2000, Authen::SASL supports passing the SMTP
server hostname and port to the OAUTHBEARER string passed via SMTP AUTH.
Add support for the same in git-send-email.

It's safe to add the new parameters unconditionally as older versions of
Authen::SASL will simply ignore them without any error. Something
similar is already being done for the authname parameter, which is not
supported by every authentication mechanism. This can be understood as
declaring a variable but not using at all.

Link: https://metacpan.org/pod/Authen::SASL::Perl::OAUTHBEARER

Signed-off-by: Aditya Garg <gargaditya08@live.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: AdityaGarg8

git-send-email.perl

@@ -1474,6 +1474,8 @@ sub smtp_auth_maybe {
 						user     => $cred->{'username'},
 						pass     => $cred->{'password'},
 						authname => $cred->{'username'},
+						host     => $smtp_server,
+						(defined $smtp_server_port ? (port => $smtp_server_port) : ()),
 					}
 				);
 				$result = $smtp->auth($sasl);