Update ruby-iso8601 to 0.12.1.
pkgsrc change: add "USE_LANGAUGES= # none".
0.12.1
Reduce the number of files that ship in the artifact (thanks @tas50).
0.12.0
Fix Months#to_seconds from November (thanks @walterbrebels).
Due to sysutils/ruby-chef's dependency, stop updating to latest version
0.12.0 for now.
## 0.11.0
* Add support for unary minus operator (thanks @walterbrebels).
## 0.10.1
* Fix `TimeInterval` size for non UTC timezones. (#41)
## 0.10.0
* Fix `TimeInterval` with `<duration>/<end>` patterns and leap years.
* Fix decimal fractions on date atoms. **WARNING** some duration patterns are
no longer valid.
ISO8601 is a simple implementation in Ruby of the ISO 8601 (Data elements and
interchange formats - Information interchange - Representation of dates
and times) standard.