added swift pm support (#456)

Author: maxxfrazer

.gitignore

@@ -34,6 +34,7 @@ playground.xcworkspace
 
 # Swift Package Manager
 .build/
+.swiftpm/
 
 # Carthage
 Carthage/Build

Package.swift

@@ -0,0 +1,21 @@
+// swift-tools-version:5.0
+// The swift-tools-version declares the minimum version of Swift required to build this package.
+
+import PackageDescription
+
+let package =   Package(
+  name: "SCLAlertView",
+  platforms: [.iOS(.v8)],
+  products: [
+    .library(name: "SCLAlertView", targets: ["SCLAlertView"]),
+  ],
+  targets: [
+    .target(name: "SCLAlertView", path: "SCLAlertView"),
+    .testTarget(
+      name: "SCLAlertViewTests",
+      dependencies: ["SCLAlertView"],
+      path: "SCLAlertViewTests"
+    )
+  ],
+  swiftLanguageVersions: [.v5]
+)