feat: Update package.json to 0.1.2

Author: github-actions[bot]

src/R3.Unity/Assets/R3.Unity/package.json

@@ -2,7 +2,7 @@
     "name": "com.cysharp.r3",
     "displayName": "R3",
     "author": { "name": "Cysharp, Inc.", "url": "https://cysharp.co.jp/en/" },
-    "version": "0.1.1",
+    "version": "0.1.2",
     "unity": "2021.3",
     "description": "Reactive Extensions for Unity.",
     "keywords": [ "rx", "event", "Scripting" ],