Support for msec time interval in Events

[ChethanSuresh]

runc events supports time intervals for msec. Example

# runc events --interval 0.5s <id>

The below line converts millisecond time.Duration API call to int, making the interval 0. Thus nil Events channel

https://github.com/containerd/go-runc/blob/9007c2405372fe28918845901a3276c0915689a1/runc.go#L352

Is there any specific reason?