Upgrade oauth2 to current version.

[fredjean]

The 0.9.x version of oauth2 still rely on the default SSL settings. As a result, it attempts to connect to the authorization server using SSLv3. It appears that your authorization server no longer support that protocol (which is a good thing due to 🐩).

Your tests are still passing after upgrading oauth2 to 1.1.0. This should address #13 .

[svenfuchs]

bitballoon-ruby is used by Travis CI https://github.com/travis-ci/dpl, and the tight requirement on oauth2 (which by itself has a pretty tight dependency on faraday) conflicts with a lot of other, more recent gems.

    bitballoon was resolved to 0.2.6, which depends on
      oauth2 (~> 1.1.0) was resolved to 1.1.0, which depends on
        faraday (< 0.10, >= 0.8)

@biilmann any chance of maybe getting this merged and released? or anyone else at BitBalloon?