Migration guide: switch master to main branch

[edgarriba]

After some years of active development to master branch, we have migrated to main to fulfill Github standards.

🔗 https://www.theserverside.com/feature/Why-GitHub-renamed-its-master-branch-to-main

As a developer, what to do ?

• If have an open PR against the old branch, please tag any of the project maintainers to help you with the rebase.

[johnnv1]

As part of this migration, the entire commit history of the repository was rewritten to make it lighter. Using the BFG Repo-Cleaner we have deleted from the history some artifacts (files >= ~0.5Mb). The complete list of these files can be checked on the commit message.

Consequently, when all branches based on the old master branch are deleted, the kornia repository will move from ~88Mb to ~14Mb. We are planning to delete these branches (and the master itself) around the date of the release v0.7.2 (end of march).

As part of this effort, in oct of 2023, we removed the unused docs build branch (see #2624), which already moved the repository from ~122Mb to ~88Mb.

So, if you want to have a lightweight fork of Kornia, I recommend you delete all branches aside from the main (be careful not to delete active branches that you have a PR on).