chore: initialize standalone UPM package

ShrinkNetwork.Integration.EventBus.asmdef

@@ -0,0 +1,19 @@
+{
+  "name": "ShrinkNetwork.Integration.EventBus",
+  "rootNamespace": "ShrinkNetwork.Integration",
+  "references": [
+    "ShrinkNetwork.Runtime",
+    "ShrinkContext.Core.Runtime",
+    "ShrinkEventBus.Runtime",
+    "UniTask"
+  ],
+  "optionalUnityReferences": [],
+  "includePlatforms": [],
+  "excludePlatforms": [],
+  "allowUnsafeCode": false,
+  "overrideReferences": false,
+  "autoReferenced": true,
+  "defineConstraints": [],
+  "versionDefines": [],
+  "noEngineReferences": false
+}