api/server/MAINTAINERS: add proppy and vieux

Docker-DCO-1.1-Signed-off-by: Johan Euphrosine <proppy@google.com> (github: proppy)

api/server/MAINTAINERS

@@ -0,0 +1,2 @@
+Victor Vieux <vieux@docker.com> (@vieux)
+Johan Euphrosine <proppy@google.com> (@proppy)