dry-validation 1.2.1 on Ruby Gems

Defining an abstract contract class that has no schema no longer crashes (issue #565) (@solnic)
Fixed an issue where Rule#each would crash when the value is not an array (issue #567) (@solnic)
Fixed an issue where guarding a rule would crash when keys are missing in the input (issue #569) (@solnic)
Added missing "pathname" require (issue #570) (@solnic)