Update README.md

Author: hacke2

README.md

@@ -23,7 +23,10 @@
 ## Getting started
 
 ### Preparation
-install Node.js >= 20
+- install Node.js >= 20
+- You can use npmmirror.com to speed up the installation in china
+> yarn config set -H npmRegistryServer "https://registry.npmmirror.com"
+> export ELECTRON_MIRROR=https://npmmirror.com/mirrors/electron/
 
 ### Start the project
 ```bash