feat(readme): require minimum capacitor-ios version

Author: codinronan

README.md

@@ -1372,6 +1372,7 @@ _Questions? [Contact us](https://support.branch.io/support/tickets/new)_
     * We strongly recommend Node >= 10.15. Node 8 might work, but it is not tested.
     * For BOTH Cordova and Capacitor, you must use Xcode >= 11.1, CocoaPods >= 1.8.4, Cordova >= 9.0.0, Ionic-CLI >= 5.1, cordova-ios >= 5.1.0
       * Every single one of these dependencies has fixes that allow the command line build, and the pod dependency resolution to work correctly
+    * You MUST use @capacitor/ios >= 1.4.0. Versions prior to that version did not federate the OpenURL notifications to other plugins, including Branch.
     * When using Capacitor, you must add the following entries yourself to `ios/App/App/Info.plist`:
       ```sh
         <key>CFBundleURLTypes</key>