Ignore json files from TypeScript type checking (facebook#5614)

Fix facebook#5613

Author: brunolemos

Diff for: config/webpack.config.dev.js

@@ -434,6 +434,7 @@ module.exports = {
         },
         reportFiles: [
           '**',
+          '!**/*.json',
           '!**/__tests__/**',
           '!**/?(*.)(spec|test).*',
           '!src/setupProxy.js',

Diff for: config/webpack.config.prod.js

@@ -554,6 +554,7 @@ module.exports = {
         },
         reportFiles: [
           '**',
+          '!**/*.json',
           '!**/__tests__/**',
           '!**/?(*.)(spec|test).*',
           '!src/setupProxy.js',