Add SPM package

Package.resolved

@@ -0,0 +1,16 @@
+{
+  "object": {
+    "pins": [
+      {
+        "package": "swift-argument-parser",
+        "repositoryURL": "https://github.com/apple/swift-argument-parser",
+        "state": {
+          "branch": null,
+          "revision": "eb51f949cdd0c9d88abba9ce79d37eb7ea1231d0",
+          "version": "0.2.0"
+        }
+      }
+    ]
+  },
+  "version": 1
+}

Package.swift

@@ -0,0 +1,28 @@
+// swift-tools-version:5.2
+// The swift-tools-version declares the minimum version of Swift required to build this package.
+
+import PackageDescription
+
+let package = Package(
+    name: "screenrecorder",
+    platforms: [
+        .macOS(.v10_14)
+    ],
+    products: [
+        .executable(
+            name: "screenrecorder",
+            targets: ["screenrecorder"]),
+    ],
+    dependencies: [
+        .package(url:"https://github.com/apple/swift-argument-parser", .exact("0.2.0")),
+    ],
+    targets: [
+        .target(
+            name: "screenrecorder",
+            dependencies: [
+                 .product(name: "ArgumentParser", package: "swift-argument-parser"),
+            ],
+            path: "ScreenRecorder/"
+        )
+    ]
+)