This PR removes the Package.Resolved file which is automatically generated / updated by Xcode or swift build when loading a swift package. The file is also added to the .gitignore, alongside other standard swift package manager ignores.

See Should Package.Resolved go in the git ignore for a discussion of the ins and out of tracking this specific file, but in summary :

Pros :

• this prevents spurious warnings about updates in that file which can happen normally as part of the dependency resolution.

Cons:

• this unpins the exact value of the dependency (swift-numerics in this case), leaving it up to the specification of Package.swift