Upgrade MadRubocop to support RuboCop 0.37

[ztoolson]

Currently MadRuboCop supports 0.36 version of RuboCop. Here are the new cops introduces in 0.37:

0.37.0

• #2620: New cop Style/ZeroLengthPredicate checks for object.size == 0 and variants, and suggests replacing them with an appropriate empty? predicate.
• Add new Style/SpaceAroundKeyword cop.
• #2745: New cop Style/MultilineHashBraceLayout checks that the closing brace in a hash literal is symmetrical with respect to the opening brace and the hash elements.
• #2761: New cop Style/MultilineMethodDefinitionBraceLayout checks that the closing brace in a method definition is symmetrical with respect to the opening brace and the method parameters.
• #2766: New cop Style/MultilineMethodCallBraceLayout checks that the closing brace in a method call is symmetrical with respect to the opening brace and the method arguments.

I'm not seeing any cops that we should disable, but I'll open up the discussion. What are your thoughts?

[ztoolson]

What the upgrade looks like in newman

[ztoolson]

//cc @liveh2o @mmmries @film42 @vintagepenguin

[jarecoo]

I'm cool with all of these.

[liveh2o]

Yeah, those all seem to be in line with our style guide. Let's cut a new version.