This is a counterpart to https://github.com/Quick/Nimble/pull/916, which added support for watchOS to Nimble.

Note that this is a draft until a new version of Nimble is released with watchOS support. Until then this points at main.

I'm also not sure if the tests will run on CI correctly because the tests require watchOS 7.4 to run and I'm not sure what version of watchOS the simulators are configured with.

I also found that the tests weren't compiling (using Xcode 13.2.1) so I've updated these too.

This PR is to add support for running on watchOS. Since Xcode 12.5 watchOS has been supported but Nimble doesn't currently compile for watchOS.

A new target has been added to the project, along with explicit support in the Package.swift.

I don't believe anything here is a breaking change.

I have a fork of Quick that also supports watchOS. I'll create a PR for that if this PR gets approved and merged.