Preparing a new version (3.1.0) - Upgrading to Xcode 11

[ecaselles]

After having managed to skip Xcode 10 😅, Xcode 11 is throwing a few warnings when building and using Kiwi.

I am putting together a new version to support Xcode 11 and while doing that, I will be reviewing any other PR that seems almost ready to go in.

If you have any changes or PRs that you would like to get into the release, please ping them here and we can work together.

Thanks!

[bamx23]

Maybe it is better to check if everything OK with Xcode 12 and make a release?

[ecaselles]

Hey @bamx23! Yes, that make sense. Have you checked it by any chance? Are there any major problems?

If there are issues and they don't seem immediate to fix, I would still try to release this version supporting Xcode 11 and then start working on a new one for Xcode 12. Does that make sense?

[bamx23]

I haven't checked Xcode 12 integration yet, but I'll try it next week.

But I think it's a good idea to release current changes anyway because I still face the same problems with the issue I fixed in #716 sometimes.

[bamx23]

I've been working with unit tests and Kiwi in Xcode 12 for about a week without any problems. No new warnings either.