feat: Add Swift Package Manager support

Author: nicholausadi

Package.swift

@@ -0,0 +1,23 @@
+// swift-tools-version:5.5
+import PackageDescription
+
+let package = Package(
+    name: "OTPFieldView",
+    platforms: [
+        .iOS("10.3")
+    ],
+    products: [
+        .library(
+            name: "OTPFieldView", 
+            targets: ["OTPFieldView"]),
+    ],
+    targets: [
+        .target(
+            name: "OTPFieldView",
+            path: "OTPFieldView",
+            exclude: [
+                "Info.plist",
+            ]
+        )
+    ]
+)