Add .mailmap
Add .mailmap

Google group started replacing sender email with the group email
recently. Here's the list of spoiled entries combined from seastar
and scylla repos

Signed-off-by: Pavel Emelyanov <c9a32589e048e044184536f7ac71ef92fe82df3e@scylladb.com>
Message-Id: <20220701160321.12080-1-c9a32589e048e044184536f7ac71ef92fe82df3e@scylladb.com>

avikivity/seastar,scylladb/seastar,syuu1228/seastar,scylladb/seastar,avikivity/seastar,syuu1228/seastar,avikivity/seastar,scylladb/seastar,syuu1228/seastar