scrooge: Add mnakamura to OWNERS
scrooge: Add mnakamura to OWNERS

RB_ID=552232

nkhuyu/scrooge,eirslett/scrooge,eirslett/scrooge,eirslett/scrooge,benhoyt/scrooge,twitter/scrooge,thirstycrow/scrooge,thirstycrow/scrooge,twitter/scrooge,benhoyt/scrooge,thirstycrow/scrooge,nkhuyu/scrooge,pnambiarsf/scrooge,benhoyt/scrooge,travisbrown/scrooge,eirslett/scrooge,twitter/scrooge,benhoyt/scrooge,nkhuyu/scrooge,benhoyt/scrooge,thirstycrow/scrooge,twitter/scrooge,travisbrown/scrooge,travisbrown/scrooge,thirstycrow/scrooge,pnambiarsf/scrooge,pnambiarsf/scrooge,nkhuyu/scrooge,nkhuyu/scrooge,travisbrown/scrooge,pnambiarsf/scrooge,pnambiarsf/scrooge