flutter pub add github

The current Dart SDK version is 3.0.3.

Because github >=7.1.0-nullsafe.0 depends on http ^0.13.0 and github <7.1.0-nullsafe.0 doesn't support null safety, every version of github requires http ^0.13.0.
So, because github_client depends on both http ^1.0.0 and github any, version solving failed.

The lower bound of "sdk: '>=1.5.0 <2.0.0 or >=2.0.0 <3.0.0'" must be 2.12.0 or higher to enable null safety.
For details, see https://dart.dev/null-safety