(maint) be explicit about expected exception

This removes the rspec warning "Using the `raise_error` matcher without providing a specific error or message risks false positives, since `raise_error` will match when Ruby raises a `NoMethodError`, `NameError` or `ArgumentError`, potentially allowing the expectation to pass without even executing the method you are intending to call."

spec/puppet/resource_api/transport/wrapper_spec.rb

@@ -109,7 +109,7 @@ class SomethingSomethingDarkside; end
 
       context 'when using method?' do
         it 'will return false' do
-          expect { instance.method :wibble }.to raise_error
+          expect { instance.method :wibble }.to raise_error NameError, %r{undefined method `wibble'}
         end
       end
     end