fix temeConfigPath for theme in project root without src.

Author: fredvd

frontend/razzle.extend.js

@@ -2,7 +2,7 @@ const plugins = (defaultPlugins) => {
   return defaultPlugins;
 };
 const modify = (config, { target, dev }, webpack) => {
-  const themeConfigPath = `${__dirname}/src/theme/theme.config`;
+  const themeConfigPath = `${__dirname}/theme/theme.config`;
   config.resolve.alias['../../theme.config$'] = themeConfigPath;
   config.resolve.alias['../../theme.config'] = themeConfigPath;