[Add] UniTask

Assets/Plugins/UniTask/package.json

@@ -0,0 +1,12 @@
+{
+    "name": "com.cysharp.unitask",
+    "displayName": "UniTask",
+    "author": { "name": "Cysharp, Inc.", "url": "https://cysharp.co.jp/en/" },
+    "version": "2.5.10",
+    "unity": "2018.4",
+    "description": "Provides an efficient async/await integration to Unity.",
+    "keywords": [ "async/await", "async", "Task", "UniTask" ],
+    "license": "MIT",
+    "category": "Task",
+    "dependencies": {}
+}