Maintainers update
Maintainers update

- Add Abhi and Chris
- Remove inactive maintainers

Signed-off-by: Flavio Crisciani <59eae1aa696b1b39cd87a38bdba3f0b2630647f9@docker.com>

abhi/libnetwork,vdemeester/libnetwork,mahak/libnetwork,vdemeester/libnetwork,medallia/libnetwork,docker/libnetwork,docker/libnetwork,mahak/libnetwork,medallia/libnetwork,abhi/libnetwork,mahak/libnetwork,medallia/libnetwork,abhi/libnetwork,docker/libnetwork,vdemeester/libnetwork