chore(package): update typescript to version 1.7.3
chore(package): update typescript to version 1.7.3

http://greenkeeper.io/
lukephills/react-typescript-boilerplate,keokilee/react-typescript-boilerplate,keokilee/react-typescript-boilerplate,joelaguero/portfolio-2017,keokilee/react-typescript-boilerplate,lukephills/react-typescript-boilerplate,MirekSz/webpack-es6-ts,joelaguero/portfolio-2017,lukephills/react-typescript-boilerplate,MirekSz/webpack-es6-ts,MirekSz/webpack-es6-ts,joelaguero/portfolio-2017