docs(deploy): 补充 Webhook 健康检查转发

deploy/nginx-github-webhook.conf

@@ -5,3 +5,8 @@ location = /github/webhook {
     proxy_set_header X-Real-IP $remote_addr;
     proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
 }
+
+location = /github/webhook-health {
+    proxy_pass http://127.0.0.1:9001/health;
+    proxy_set_header Host $host;
+}