title: Flutter CocoaPods could not find compatible versions for pod OneSignalXCFramework
body: <p>on running <code>pod install</code> there is appearing following error</p>
  <pre><code>[!] CocoaPods could not find compatible versions for pod &quot;OneSignalXCFramework&quot;:
    In Podfile:
      onesignal_flutter (from `.symlinks/plugins/onesignal_flutter/ios`) was resolved to 3.2.7, which depends on
        OneSignalXCFramework (= 3.9.1)
  
  None of your spec sources contain a spec satisfying the dependency: `OneSignalXCFramework (= 3.9.1)`.
  
  You have either:
   * out-of-date source repos which you can update with `pod repo update` or with `pod install --repo-update`.
   * mistyped the name or version.
   * not added the source repo that hosts the Podspec to your Podfile.
  </code></pre>