Avoid exclusive language `master`

[rocketeerbkw]

There has already been discussion and agreement internally to no longer use master as the name of our default branch. This issue is to announce our intention publicly and hold us accountable for the change (since it's already been ~2 months from our last discussion).

TODO:

• Determine what processes are needed to make the change
• Make the change

[smlx]

I found a couple of things while looking into this:

There's a nice procedure here which will allow you to gradually migrate by using github actions to mirror commits between main and master branches during a transition phase.

There was also a change in git 2.28 to make the default branch name configurable in git init.

[tobybellwood]

as per https://github.com/github/renaming/ - there are already some protections in place - missing branches now redirect to the default.

After renaming, we'd need to modify any PRs to point to main, and look at the configuration of the release drafter Action.

[smlx]

On the PR retargeting, there's a script here https://github.com/ethomson/retarget_prs

[dan2k3k4]

Hey @AlannaBurke, I've created PR #2446 and updated as much usage of master as possible.

There are still various links to 3rd party repositories but those still use master branch as their default branch.

I am not 100% sure on the tests/ directory, I updated it but if those should be ignored then I can remove the commit for that.

Each commit refers to a different set of root directories (e.g. update to all docs/ is done in one commit).

[dan2k3k4]

We may need to also update Pygmy to use main branch as default, if so, we will need to update all of the links to the current documentation for Pygmy which is https://pygmy.readthedocs.io/

[rocketeerbkw]

We still have a master branch until we release lagoon 2 (on main) and the potential work for pygmy too, so reopening.

[rocketeerbkw]

I can only find a few remaining issues in legacy repos that will eventually be archived so I think we've completed this.