Updates Package.swift for Swift Tools 5.5

Author: davidcairns

Package.swift

@@ -1,5 +1,23 @@
+// swift-tools-version:5.5
+// The swift-tools-version declares the minimum version of Swift required to build this package.
+
 import PackageDescription
 
 let package = Package(
-    name: "TSAO"
+    name: "TSAO",
+    platforms: [
+        .iOS(.v14),
+    ],
+    products: [
+        .library(
+            name: "swift_tsao",
+            targets: ["swift_tsao"]
+        ),
+    ],
+    targets: [
+        .target(
+            name: "swift_tsao",
+            path: "./Sources"
+        ),
+    ]
 )