devel/ruby-backports: update to 3.14.0

== Version 3.14.0 - April 29th, 2019

  * Hash
    * +to_h+ (with block)

== Version 3.13.0 - April 5th, 2019

  * Hash
    * +merge+, +merge!+/+update+ (with multiple arguments)

== Version 3.12.0 - February 20th, 2019

* New Ruby version 2.6.0
  * Array
    * +difference+, +union+
    * +to_h+ (with block)
  * Enumerable
    * +chain+
    * +to_h+ (with block)
  * Enumerator::Chain (use Enumerable#chain)
  * Kernel
    * +then+

* Additional backports for 2.5.0:
  * String
    * +undump+

(taca)