An owner of this repository has limited the ability to open a pull request to users that are collaborators on this repository.

 git 无法发起：pull request，提示：An owner of this repository has limited the ability to open a pull request to users that are collaborators on this repository.

原因是 base/ forked repository 的管理员开启了 interaction_limits。点击 disable 按钮，关闭即可。