add prometheus_listen_port to example (#8)

example/distributed-with-obproxy-example.yaml

@@ -50,6 +50,7 @@ obproxy:
     - 192.168.1.5
   global:
     listen_port: 2883
+    prometheus_listen_port: 2884
     home_path: /root/obproxy
     # oceanbase root server list
     # format: ip:mysql_port,ip:mysql_port

example/mini-distributed-with-obproxy-example.yaml

@@ -61,6 +61,7 @@ obproxy:
     - 192.168.1.5
   global:
     listen_port: 2883
+    prometheus_listen_port: 2884
     home_path: /root/obproxy
     # oceanbase root server list
     # format: ip:mysql_port,ip:mysql_port

example/mini-single-with-obproxy-example.yaml

@@ -45,6 +45,7 @@ obproxy:
     - 192.168.1.2
   global:
     listen_port: 2883
+    prometheus_listen_port: 2884
     home_path: /root/obproxy
     # oceanbase root server list
     # format: ip:mysql_port,ip:mysql_port

example/single-with-obproxy-example.yaml

@@ -35,6 +35,7 @@ obproxy:
     - 192.168.1.2
   global:
     listen_port: 2883
+    prometheus_listen_port: 2884
     home_path: /root/obproxy
     # oceanbase root server list
     # format: ip:mysql_port,ip:mysql_port