Update README.md

Author: yunlzheng

README.md

@@ -1,6 +1,6 @@
 ## Alertmanager Dingtalk Webhook
 
-Webhook service support send Prometheus 2.0 alert message to Dingtalk。
+Webhook service support send Prometheus 2.0 alert message to Dingtalk.
 
 ## How To Use
 
@@ -31,4 +31,4 @@ groups:
       summary: "Instance {{ $labels.instance }} CPU usgae high"
       description: "{{ $labels.instance }} CPU usage above 85% (current value: {{ $value }})"
       dingtalkRobot: "https://oapi.dingtalk.com/robot/send?access_token=xxxx"
-```
+```