[OPR-164]: Adds Package.swift
[OPR-164]: Adds Package.swift

No idea what I'm doing with this yet.

ProcedureKit/ProcedureKit,cezarywojcik/Operations,blg-andreasbraun/Operations,blg-andreasbraun/Operations,danthorpe/Operations,ProcedureKit/ProcedureKit,blg-andreasbraun/Operations,blg-andreasbraun/ProcedureKit,ProcedureKit/ProcedureKit,blg-andreasbraun/ProcedureKit,danthorpe/Operations,blg-andreasbraun/ProcedureKit,cezarywojcik/Operations,danthorpe/Operations,cezarywojcik/Operations