Bumping the tzinfo version to 1.2.2

This is the ruby timezone library. I've ran the tests and everything passes.

In the version of Rails I'm using (4.1.5), activesupport has `tzinfo (~> 1.1)`
Since this gem is designed to be used with Rails I'm not sure it makes sense to have a more prescriptive dependency, but I'm happy to be corrected on that.