Update xcov-core with fat binary

[victor]

Seeing as how the pre-built binary did not work on Apple Silicon (without Rosetta, which many devs refuse to install for reasons) I went to the source repo, enabled the fat binary setting, and just built the binary again.

I didn't use any particular signature, in a separate machine of mine I only had to right-click it once to remove the quarantine bit, but I suspect on other people's machines it may not work.

Also, as with anything pre-built from an unknown dev, exercise caution. I don't belong to the fastlane project, I just saw other people in the same situation as me and decided to give it a try, I am providing the binary as a convenience but you don't have to trust me. Build the binary yourself and compare the results (though at that point, you're better off using yours)