README.md: update travis url
README.md: update travis url

kanreisa/Mirakurun,upsilon/Mirakurun,Chinachu/Mirakurun,kanreisa/Mirakurun,Chinachu/Mirakurun,upsilon/Mirakurun,akimasa/Mirakurun,Chinachu/Mirakurun,upsilon/Mirakurun,akimasa/Mirakurun,kanreisa/Mirakurun,akimasa/Mirakurun,Chinachu/Mirakurun