Implemented according to new specification of Alerts API.

[yaminoma]

This Pull Request implements it according to the new specification of the Alerts API.
ref: mackerelio/mackerel-client-go#82

[yaminoma]

Thanks. I fixed the part you pointed out.

[astj]

Oh, and it's better to colorize OK status with green color.

mkr/alerts.go

Lines 196 to 205 in ab09551

	if colorize {
	switch alert.Status {
	case "CRITICAL":
	statusMsg = color.RedString("CRITICAL")
	case "WARNING":
	statusMsg = color.YellowString("WARNING ")
	case "UNKNOWN":
	statusMsg = "UNKNOWN "
	}
	}

[yaminoma]

Thanks👍

[astj]

👍