feat: 调整版本支持配置

Package.swift

@@ -1,4 +1,4 @@
-// swift-tools-version: 6.1
+// swift-tools-version: 5.9
 // The swift-tools-version declares the minimum version of Swift required to build this package.
 
 import PackageDescription
@@ -9,7 +9,7 @@ let package = Package(
     name: "AutoCodable",
     platforms: [
         .macOS(.v10_15),
-        .iOS(.v13)
+        .iOS(.v12)
     ],
     products: [
         // Products define the executables and libraries a package produces, making them visible to other packages.