* Fix display time of milestones
* Move the SecToTime function
From the models/issue_stopwatch.go file to the modules/util package
* Rename the sec_to_time file
* Updated formatting
* Include copyright notice in sec_to_time.go
* Apply PR review suggestions
- Update copyright notice dates to 2022
- Change `1 day 3h 5min 7s` to `1d 3h 5m 7s`
* Rename hrs var and combine conditions
* Update unit tests to match new time pattern
Changed `1min` to `1m`
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>