Allow HTTParty 0.14
Allow HTTParty 0.14

HTTParty 0.14 removes dependency to JSON gem and is thus compatible
with Ruby 2.4.

Gitlab 3.7 locks to HTTParty 0.13, but the next version will drop that requirement. Using Gitlab 3.6 should also work.
mvz/pronto,mmozuras/pronto,aergonaut/pronto,prontolabs/pronto