rename gitea's default branch for new repos
currently, when creating a fresh repo on this gitea instance, the repo is initialised with a default
given that we're moving away from that… naming scheme, it would be nice if we didn't have to do the dance of renaming the default branch of newly created repos to begin with
It should now be
main (won't change a thing for existing repos though). Feel free to reopen if you have a better naming idea
Deleting a branch is permanent. It CANNOT be undone. Continue?