MAINTAINERS: add Kir Kolyshkin
MAINTAINERS: add Kir Kolyshkin

Kir has been the most active contributor recently:
https://github.com/opencontainers/runc/pulls?q=is%3Apr+author%3Akolyshkin+

Signed-off-by: Akihiro Suda <10ddef0dea2a66ab193b07198faa879adcb213d8@hco.ntt.co.jp>

xiaochenshen/runc,opencontainers/runc,xiaochenshen/runc,dqminh/runc,estesp/runc,kolyshkin/runc,rhatdan/runc,opencontainers/runc,kolyshkin/runc,kolyshkin/runc,rhatdan/runc,mikebrow/runc,mikebrow/runc,dqminh/runc,opencontainers/runc,dqminh/runc,rhatdan/runc,opencontainers/runc,dqminh/runc,estesp/runc,estesp/runc,xiaochenshen/runc,rhatdan/runc,mikebrow/runc,kolyshkin/runc