devel/ruby-mocha: update to 1.15.0

1.15.0 (2022-09-21)

External changes

* Fix examples using mock constructor with block (1cc17667)
* Add another example for API#sequence (b7a7d233, #59)
* Remove support for Ruby v1.8 (ddb5d672)
* Deprecate support for Ruby versions earlier than v2.0 - thanks to
  @wasabigeek (#553, #555)

Internal changes

* Update instructions for obtaining Rubygems API key (ed9c040a)
* Consistent definitions for respond_to? methods (#533)
* Run test tasks before release tasks (92a1bc6e, #447)
* Fix test:performance Rake task (#538, #539)
* Tidying following removal of support for Ruby v1.8 - thanks to @nitishr
  (#542)
* Remove ParametersMatcher from Invocation#call_description - thanks to
  @wasabigeek (#543)
* Remove unnecessary splatting in Invocation - thanks to @wasabigeek (#549)
* Extract handle_method_call from method_missing - thanks to @wasabigeek
  (#550)

(taca)