Update the gemspec so it follows the revision number

Update the gemspec so it follows the revision number listed in the breaking changes file.

```cucumber
Given I want to know the latest revision of data I can reference in Store while using ember-rails
When I look my Gemfile.lock
Then I would like to see the same number used for the gem version that is used in the breaking changes file.
```

Perhaps here is a reason that this is not the case but just in case it was a time vs priority thing I though I would offer it as a PR. Cheers.