Rename `master` branch to `main`

[corubba]

There is an effort in the git- and opensource-community to move away from master as the name for the default branch, and establish the less negative annotated and more descriptive name main instead. I recommend this excellent article for an overview.

I would like to propose to follow suit and rename the default branch from master to main.

The impact of this should be very minimal. End-users using a pre-packaged build from their linux distribution won't be effected at all. Neither are downstream packagers that use the release-source-archives, since those won't change. Should they build directly from git instead, then it is a reasonably trivial one-off change on their side. The same goes for contributors, it means a simple one-off change to their local repository.

GitHub also offers some guidance and tool-support for this. A short list of things I could think of that additionally will need modifications:

• Update the documentation, there are various references
• Update the CI/workflows
• Inform about this change, I think a pinned informational issue should suffice

[sandrotosi]

while i welcome positive-intended changes, my personal view is that i kinda struggle to see the actual benefit of the rename, in particular given the additional work that it requires (by just looking at the 3 points alone you mentioned). i dont know

[corubba]

If nothing else I wanted to raise the issue and start a discussion. I agree that it does not have any immediate benefit for the project, it would just support the establishment of the new standard. Closing the issue as "Won't fix" is absolutely acceptable. Of the actual changes that need to be done, I surmise 95% will be carried out by the github tooling and a search&replace sweep.