chore: add code formatting and linting (#952)

packages/netlify-cms/webpack.config.js

@@ -13,8 +13,8 @@ const baseConfig = {
   entry: './index.js',
   plugins: [
     ...Object.entries(plugins)
-      .filter(([ key ]) => key !== 'friendlyErrors')
-      .map(([ , plugin ]) => plugin()),
+      .filter(([key]) => key !== 'friendlyErrors')
+      .map(([, plugin]) => plugin()),
     new webpack.DefinePlugin({
       NETLIFY_CMS_VERSION: JSON.stringify(`${pkg.version}${isProduction ? '' : '-dev'}`),
       NETLIFY_CMS_CORE_VERSION: null,
@@ -44,10 +44,7 @@ if (isProduction) {
      */
     {
       ...baseConfig,
-      entry: [
-        path.join(__dirname, 'scripts/deprecate-old-dist.js'),
-        baseConfig.entry,
-      ],
+      entry: [path.join(__dirname, 'scripts/deprecate-old-dist.js'), baseConfig.entry],
       output: {
         ...baseConfig.output,
         filename: 'dist/cms.js',