Update correct list of default NTP hosts (#2661)
Update correct list of default NTP hosts (#2661)

The host starting with 0 was missing from this documentation. After seeing it blocked, and checking the agent code, this update would correct it.

* [V5 agent code](https://github.com/DataDog/dd-agent/blob/33afda662aade99500f454b33f208e8289818d7b/utils/ntp.py#L32)
* [V6 agent code](https://github.com/DataDog/datadog-agent/blob/53b8106642411f2e992acc52bf6303de22c072a8/pkg/collector/corechecks/net/ntp_test.go#L300)
DataDog/integrations-core,DataDog/integrations-core,DataDog/integrations-core,DataDog/integrations-core,DataDog/integrations-core,DataDog/integrations-core,DataDog/integrations-core,DataDog/integrations-core,DataDog/integrations-core,DataDog/integrations-core