SemanticPuppet::Dependency::ModuleRelease should implement operator eql? and operator '=='

The SemanticPuppet::Dependency::ModuleRelease class does not implement eql? or '==' which, when using Ruby versions >= 2.3.0 means that when compared using '==', it ends up in '<=>'. That method simply assumes that its argument is a SemanticPuppet::Dependency::ModuleRelease which then fails when a release is compared to something else. Example:

mod_rel == nil

results in the following error:

undefined method `priority' for nil:NilClass

     # "./lib/semantic_puppet/dependency/module_release.rb:36:in `<=>'