Support unity package manager

Author: asus4

README.md

@@ -14,4 +14,12 @@ Add `TapticPlugin/Samples/Sample UI` and `TapticPlugin/Sample/Sample Ball` into
 - iPhone 7 / iPhone 7 Plus or later
 
 ![](image/capture1.png)
-![](image/capture2.png)
+![](image/capture2.png)
+
+## Unity Package Manager
+
+if you are using Unity Package Manager,
+
+Open `Packages/manifest.json` and add following line into `dependencies`.
+
+`"com.github.asus4.unity-taptic-plugin": "https://github.com/asus4/unity-taptic-plugin.git#upm"`