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

Fix facebook#5613

Author: brunolemos

packages/react-scripts/config/webpack.config.dev.js

@@ -428,6 +428,7 @@ module.exports = {
         },
         reportFiles: [
           '**',
+          '!**/*.json',
           '!**/__tests__/**',
           '!**/?(*.)(spec|test).*',
           '!src/setupProxy.js',

packages/react-scripts/config/webpack.config.prod.js

@@ -548,6 +548,7 @@ module.exports = {
         },
         reportFiles: [
           '**',
+          '!**/*.json',
           '!**/__tests__/**',
           '!**/?(*.)(spec|test).*',
           '!src/setupProxy.js',