update doc

README.md

@@ -147,7 +147,7 @@ You **MUST** use this command to copy the certs to the target files, **DO NOT**
 
 **Apache** example:
 ```bash
-acme.sh --installcert -d example.com \
+acme.sh --install-cert -d example.com \
 --certpath      /path/to/certfile/in/apache/cert.pem  \
 --keypath       /path/to/keyfile/in/apache/key.pem  \
 --fullchainpath /path/to/fullchain/certfile/apache/fullchain.pem \
@@ -156,7 +156,7 @@ acme.sh --installcert -d example.com \
 
 **Nginx** example:
 ```bash
-acme.sh --installcert -d example.com \
+acme.sh --install-cert -d example.com \
 --keypath       /path/to/keyfile/in/nginx/key.pem  \
 --fullchainpath /path/to/fullchain/nginx/cert.pem \
 --reloadcmd     "service nginx force-reload"