Add Appraisal gemset for Capybara 2 and 3

[mattheworiordan]

See #236 (review) for backgruond.

[eiapopeia]

I also see the warning:
capybara-screenshot could not detect a screenshot driver for 'apparition'. Saving with default with unknown results.
The screenshot itself looks really well, thought.

Gems:

• apparition (0.2.0)
• capybara (3.20.2)
• capybara-screenshot (1.0.22)

[sedubois]

I also got that warning when using apparition. Similar to the solution in #22, I've added this to my rails_helper.rb and it seems to work: Capybara::Screenshot.register_driver(:apparition, &:save_screenshot).

[eiapopeia]

Thanks for the hint. This fixes the message for me.

I think it should be already built in because apparition driver will be the default in the future.

[mattheworiordan]

@eiapopeia @sedubois sorry for the slow reply on this. I agree apparition is likely to win the battle here. Would either of you be willing to do a PR with my help?

[mattheworiordan]

See https://github.com/mattheworiordan/capybara-screenshot/pull/219/files for a related PR