Time to delete the old `master` branches?

[sbc100]

The spec repo (and it seems all the of forks) have a master branch which IIUC automatically tracks main. There was recently a change that disappeared because it was merged in the master instead of main: https://github.com/WebAssembly/memory64/pull/60#issuecomment-2168642148

Does anyone still rely on these master branch names? Can we remove them at this point? I assume they were intended only to exist for some transitional period.

[tlively]

Removing them sgtm.

[sbc100]

OK I'll start by removing master from the proposals repos that I champoin (memory64 + extended const)

[sbc100]

I'm deleted the old master branch from the two proposal repos that I control. No issues reported.

@tlively @dschuff @rossberg perhaps one of you could delete the one from the main spec and design repos (and any repos your champion perhaps too).

[rossberg]

I assume that requires first removing the github action for cross-sync? Maybe we should do that in the spec repo, so that it can be downstreamed to all proposals?

[rossberg]

PTAL at #1760.