Fix Xcode 12 warning IPHONEOS_DEPLOYMENT_TARGET

Fixes the warning 
The iOS Simulator deployment target 'IPHONEOS_DEPLOYMENT_TARGET' is set to 8.0, but the range of supported deployment target versions is 9.0 to 14.2.99.

Author: massimobio

Package.swift

@@ -5,7 +5,7 @@ let package = Package(
     name: "KissXML",
     platforms: [
         .macOS(.v10_10),
-        .iOS(.v8),
+        .iOS(.v9),
         .tvOS(.v9),
         .watchOS(.v2)
     ],