remove uneccessary target.browsers (#1004)
remove uneccessary target.browsers (#1004)

options are already defined in package.json's "browserList" field.
neonblack-at/webpack,twcapps/vue-typescript-boilerplate,neonblack-at/webpack,neonblack-at/webpack,Toilal/vue-webpack-template,vuejs-templates/webpack,Toilal/vue-webpack-template,twcapps/vue-typescript-boilerplate,vuejs-templates/webpack,vuejs-templates/webpack,twcapps/vue-typescript-boilerplate,twcapps/vue-typescript-boilerplate,Toilal/vue-webpack-template,Toilal/vue-webpack-template