Fix build, and fix xcodeproj missing files

[s2mr]

When using the latest swiftlint 0.51.0, xcodeproj's prebuild script occurs a fatal error. So, the build failed for users who use carthage and install the latest swiftlint.

And, xcodeproj file contains missing reference files. So I deleted it.

This PR contains the following:

• [x] Fix swiftlint serious violations.
• [x] Delete missing reference in xcodeproj
• [x] Equal xcodeproj's ios minimum development target to Package.swift

Environment:

• carthage 0.39.0
• swiftlint 0.51.0
• Xcode 14.2.0
• Mac OS Ventura 13.2.1（22D68）

[ddanielczyk]

+1