add unity version

Author: András Kurai

UnityResourceGenerator/Assets/UnityResourceGenerator/package.json

@@ -1,10 +1,11 @@
 {
     "name": "com.autsoft.unityresourcegenerator",
+    "version": "0.1.0",
     "displayName": "Unity Resource Generator",
     "description": "Generate path strings for Resources.Load",
     "license": "MIT",
     "changelogUrl": "https://github.com/AutSoft/UnityResourceGenerator/blob/main/CHANGELOG.md",
-    "version": "0.1.0",
+    "unity": "2019.4",
     "keywords": [
         "Editor",
         "Resources"