Convert specs to RSpec 2.99.0 syntax with Transpec

This conversion is done by Transpec 2.2.1 with the following command:
    transpec -b true,false

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

* 13 conversions
    from: be_true
      to: be true

* 12 conversions
    from: be_false
      to: be false

* 2 conversions
    from: obj.should_not
      to: expect(obj).not_to

For more details: https://github.com/yujinakayama/transpec#supported-conversions