Add basic SwiftPM manifest file

Author: Jeehut

Package.swift

@@ -0,0 +1,14 @@
+// swift-tools-version:4.2
+import PackageDescription
+
+let package = Package(
+    name: "AlignedCollectionViewFlowLayout",
+    products: [
+        .library(name: "AlignedCollectionViewFlowLayout", targets: ["AlignedCollectionViewFlowLayout"])
+    ],
+    targets: [
+        .target(
+            name: "AlignedCollectionViewFlowLayout"
+        )
+    ]
+)