docs: add minimum supported versions for SDKs (#184)

🎫 Ticket: https://linear.app/stream/issue/XYZ-123

📑 Docs: https://github.com/GetStream/docs-content/pull/<id>

### 💡 Overview

### 📝 Implementation notes

Author: szuperaz

packages/react-native-sdk/README.md

@@ -1,3 +1,7 @@
+Supported React versions: >=17.0.0
+Supported React Native versions: >=0.73.0
+Supported Expo versions: >=51.0.0
+
 # react-native-sdk
 
 This library was generated with [Nx](https://nx.dev).

packages/react-sdk/README.md

@@ -0,0 +1 @@
+Supported React versions: >=17.0.0