Update README.md

fix code edit

Author: zero-zoro

README.md

@@ -1,5 +1,8 @@
 # free-ssh-vpn-panel
 a free ssh-vpn panel
 
-#how to install
-wget https://raw.githubusercontent.com/zero-zoro/free-ssh-vpn-panel/main/ssh-vpn_install.sh && bash ssh-vpn_install.sh
+## How to install?
+```
+$ wget https://raw.githubusercontent.com/zero-zoro/free-ssh-vpn-panel/main/ssh-vpn_install.sh && bash ssh-vpn_install.sh
+```
+