create or update all the files in a single commit

[mgaitan]

Currently we are iterating over the list of files to upload and the relying on create_file (or update_file) to commit the changes. It produce a commit per file and it could be slow

It's possible to commit all the changes in a single commit

check

• https://github.com/Nautilus-Cyberneering/pygithub/blob/main/src/04_sign_commit_with_multiple_files_using_github_api.py
• [Example] Full example of commit multiple file PyGithub/PyGithub#1628