cluster: wrong ngm config

[kaaaaaaang]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. What did you do?

2. What did you expect to see?

right pd address in config file like ["127.0.0.1:2379", "127.0.0.1:2339"]

3. What did you see instead?

wrong pd address in config file like ["127.0.0.1:2379" "127.0.0.1:2339"]

4. What version of TiUP are you using (tiup --version)? v1.12.0