...
pip install github-issues-tools
Once installed, just follow the useful CLI prompts.
$ github-issues-tools -h
usage: github-issues-tools [-h] {export-labels,copy-labels} ...
positional arguments:
{export-labels,copy-labels}
export-labels Export all labels from a repository.
copy-labels Copies labels from one repository to another.
optional arguments:
-h, --help show this help message and exit