[Feature Request] Support days for --since

[aoyama-val]

It would be great if we could specify like:

utern --since 3d
(since 3 days ago)

[sakamossan]

utern uses time.ParseDuration internally.

utern/config/config.go

Lines 42 to 43 in 448ee83

	since := c.String("since")
	startDuration, err := time.ParseDuration(since)

And time.ParseDuration seems to have a policy of not accepting days.

• flag: let Duration accept days · Issue #11473 · golang/go

So for now, you can use options like 72h instead of 3d.