Update Unity package.json to target Unity 2022.3.

PiperOrigin-RevId: 954900815

Author: Mobile Ads Developer Relations

packages/com.google.ads.mobile/package.json

@@ -14,7 +14,8 @@
     "url": "https://github.com/googleads/googleads-mobile-unity"
   },
   "description": "The Google Mobile Ads package allows you to easily monetize your Unity apps for iOS and Android using Google's native iOS and Android Mobile SDKs via a unified C# API in Unity.",
-  "unity": "2019.4",
+  "unity": "2022.3",
+  "unityRelease": "0f1",
   "samples": [
     {
       "displayName": "GMA Unity Sample App",