Add PromiseKit dependency

- Added PromiseKit dependency

Carthage/Checkouts/PromiseKit/Extensions/UIKit/Sources/UIViewPropertyAnimator+Promise.swift

@@ -0,0 +1,14 @@
+#if !PMKCocoaPods
+import PromiseKit
+#endif
+import UIKit
+
+@available(iOS 10, tvOS 10, *)
+public extension UIViewPropertyAnimator {
+    func startAnimation(_: PMKNamespacer) -> Guarantee<UIViewAnimatingPosition> {
+        return Guarantee {
+            addCompletion($0)
+            startAnimation()
+        }
+    }
+}