[Update] Update supported platforms version

Author: rakuyoMo

Package.swift

@@ -5,10 +5,10 @@ import PackageDescription
 let package = Package(
     name: "APIWrapper",
     platforms: [
-        .iOS(.v11),
-        .macOS(.v10_13),
-        .tvOS(.v11),
-        .watchOS(.v4)
+        .iOS(.v12),
+        .macOS(.v10_14),
+        .tvOS(.v12),
+        .watchOS(.v5),
     ],
     products: [
         .library(name: "APIWrapper", targets: ["APIWrapper"]),