Update gem versions
Convert specs to RSpec 3.1.0 syntax with Transpec

This conversion is done by Transpec 3.0.1 with the following command:
    transpec

* 10 conversions
    from: obj.should
      to: expect(obj).to

* 1 conversion
    from: obj.stub(:message)
      to: allow(obj).to receive(:message)

For more details: https://github.com/yujinakayama/transpec#supported-conversions
Remove deprecated RSpec config

RSpec::Core::Configuration#treat_symbols_as_metadata_keys_with_true_values= is deprecated, it is now set to true as default and setting it to false has no effect.
Merge pull request #2 from thiagogabriel/update-gems

Update bundler and RSpec