MAINTAINERS: update email of Peter Lieven

I will leave KAMP in the next days. Update email to stay reachable.

Signed-off-by: Peter Lieven <pl@kamp.de>
Message-ID: <20230105095039.182718-1-pl@kamp.de>
Signed-off-by: Thomas Huth <thuth@redhat.com>
1 file changed