CONTRIBUTING: update to new commit style
CONTRIBUTING: update to new commit style

flandr/fleet,mwhooker/fleet,octoblu/fleet,dalbani/fleet,flandr/fleet,mwitkow-io/fleet,improbable-io/fleet,bcwaldon/fleet,dongsupark/fleet,bcwaldon/fleet,coreos/fleet,mwitkow-io/fleet,hhoover/fleet,octoblu/fleet,coreos/fleet,wuqixuan/fleet,esatterwhite/fleet,mwitkow/fleet,bcwaldon/fleet,jonboulle/fleet,jonboulle/fleet,mischief/fleet,paveltiunov/fleet,paveltiunov/fleet,giantswarm/fleet,mwitkow/fleet,coreos/fleet,endocode/fleet,dongsupark/fleet,mookjp/fleet,WPMedia/fleet,dalbani/fleet,bviswana101/fleet,dalbani/fleet,improbable-io/fleet,webwlsong/fleet,endocode/fleet,endocode/fleet,ecnahc515/fleet,mookjp/fleet,mwhooker/fleet,thepwagner/fleet,ecnahc515/fleet,ecnahc515/fleet,wuqixuan/fleet,bviswana101/fleet,WPMedia/fleet,jonboulle/fleet,improbable-io/fleet,giantswarm/fleet,thepwagner/fleet,hhoover/fleet,dongsupark/fleet,mischief/fleet,giantswarm/fleet,esatterwhite/fleet,webwlsong/fleet