mailmap: add entries for Serge Hallyn's dead accounts

Signed-off-by: Serge Hallyn <serge@hallyn.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>

.mailmap

@@ -535,6 +535,8 @@ Sebastian Reichel <sre@kernel.org> <sebastian.reichel@collabora.co.uk>
 Sebastian Reichel <sre@kernel.org> <sre@debian.org>
 Sedat Dilek <sedat.dilek@gmail.com> <sedat.dilek@credativ.de>
 Senthilkumar N L <quic_snlakshm@quicinc.com> <snlakshm@codeaurora.org>
+Serge Hallyn <sergeh@kernel.org> <serge.hallyn@canonical.com>
+Serge Hallyn <sergeh@kernel.org> <serue@us.ibm.com>
 Seth Forshee <sforshee@kernel.org> <seth.forshee@canonical.com>
 Shannon Nelson <shannon.nelson@amd.com> <snelson@pensando.io>
 Shannon Nelson <shannon.nelson@amd.com> <shannon.nelson@intel.com>