Updated build instructions to use the swift package manager to install ArcGIS Runtime 100.12.0 with commits 31e680798b80faacb08d4dc6a4c99e1c1d5f02ea and f6e1f9429e68b35355f075876d66be5f269a0d6c.
Removed iOS 14 deprecations with commit 886ff51ad4aed72552aaeb51c32b9ecc5750b74c
Removed iOS15 deprecations with commit e0cd24d43c2a4232c7cce0184b039d659fe3cada
Tested build with Xcode 13, Swift 5.5 and SwiftUI 3, however there were no required changes to the code or build instructions.