Implementation Issue with RevenueCat SDK for Amazon App Store in Flutter

I am currently facing an issue while trying to implement the RevenueCat SDK in a Flutter project for the Amazon App Store. I have followed the documentation provided for integrating RevenueCat with Flutter, but I am encountering errors during the process. (https://www.revenuecat.com/docs/flutter#amazon-appstore)

Issue:
The problem arises when I add the RevenueCat SDK dependencies to my Flutter project as instructed in the documentation. After adding these dependencies, running flutter run results in errors.

Code:

purchases_flutter:
    git:
      url: git://github.com/revenuecat/purchases-flutter.git
      ref: amazon.alpha.3

Error:

Git error. Command: git fetch
stdout: 
stderr: fatal: unable to connect to github.com:
github.com[0: 140.82.121.3]: errno=Operation timed out