Update macOS deployment target

from v10_16 to v11 since Apple finally got their version numbers correct

Author: amayers

Package.swift

@@ -5,7 +5,7 @@ import PackageDescription
 
 let package = Package(
     name: "NumericText",
-    platforms: [.iOS(.v14), .macOS(.v10_16), .watchOS(.v7), .tvOS(.v14)],
+    platforms: [.iOS(.v14), .macOS(.v11), .watchOS(.v7), .tvOS(.v14)],
     products: [
         .library(
             name: "NumericText",