mailmap: add entry for myself

I no longer work at Savoir-faire Linux but even though MAINTAINERS is
up-to-date, some emails are still sent to my old email address.
Signed-off-by: Vivien Didelot <vivien.didelot@gmail.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>

.mailmap

@@ -265,6 +265,7 @@ Vinod Koul <vkoul@kernel.org> <vkoul@infradead.org>
 Viresh Kumar <vireshk@kernel.org> <viresh.kumar@st.com>
 Viresh Kumar <vireshk@kernel.org> <viresh.linux@gmail.com>
 Viresh Kumar <vireshk@kernel.org> <viresh.kumar2@arm.com>
+Vivien Didelot <vivien.didelot@gmail.com> <vivien.didelot@savoirfairelinux.com>
 Vlad Dogaru <ddvlad@gmail.com> <vlad.dogaru@intel.com>
 Vladimir Davydov <vdavydov.dev@gmail.com> <vdavydov@virtuozzo.com>
 Vladimir Davydov <vdavydov.dev@gmail.com> <vdavydov@parallels.com>