Draft: Phlex 2 support

[triskweline]

This is a draft PR that adds support for Phlex 2.1 (and drops support for Phlex 1).

So far I fixed the tests and all deprecation warnings. I didn't do any testing beyond that.

[joelmoss]

Amazing! Thanks for this, but I don't want to drop support for Phlex 1 just yet. I still use it heavily, and rely a lot on some of the things changed or removed in Phlex 2.

Version detection of Phlex would be best here. Any chance you could add that, so that these changes are only applied when Phlex 2+ is used?

[triskweline]

I added version switches for Phlex 1/2.

I also added the appraisals gem to run tests for various Phlex versions. Tested gem sets are defined in the Appraisal file.

To run tests for all supported Phlex versions:

bundle exec appraisal sus

To run tests for a specific Phlex versions, call:

bundle exec appraisal phlex-1 sus
bundle exec appraisal phlex-2 sus

Again, I only made sure the tests pass, but did no manual testing beyond that.

[joelmoss]

Thanks loads. Will take a look.