add vieux as server's MAINTAINERS

Docker-DCO-1.1-Signed-off-by: Victor Vieux <vieux@docker.com> (github: vieux)

server/MAINTAINERS

@@ -1 +1,2 @@
 Solomon Hykes <solomon@docker.com> (@shykes)
+Victor Vieux <victor.vieux@docker.com> (@vieux)