Support SwiftPM

Author: shtnkgm

Package.swift

@@ -0,0 +1,21 @@
+// swift-tools-version:5.0
+import PackageDescription
+
+let package = Package(
+    name: "ImageTransition",
+    platforms: [.iOS("12.0")],
+    products: [
+        .library(
+            name: "ImageTransition",
+            targets: ["ImageTransition"])
+    ],
+    dependencies: [],
+    targets: [
+        .target(
+            name: "ImageTransition",
+            dependencies: []),
+        .testTarget(
+            name: "ImageTransitionTests",
+            dependencies: ["ImageTransition"])
+    ]
+)

README.md

@@ -22,15 +22,9 @@ Something looks like below:
 
 ## Installation
 
-### Carthage
-
- - Add `github "shtnkgm/ImageTransition"` to your Cartfile.
- - Run carthage update.
- 
-### CocoaPods
-
- - Add `pod 'ImageTransition'` to your podfile.
- - Run pod update.
+ - Swift Package Manager: `https://github.com/shtnkgm/ImageTransition.git`
+ - Carthage: `github "shtnkgm/ImageTransition"` 
+ - CocoaPods: `pod "ImageTransition"`
 
 ## Usage