rename default branch to main

[marcoieni]

Is this enough? Or some other repo depends on master?

Related to rust-lang/infra-team#227

before merging this:

• change the branch name in the settings
• update the branch name in https://github.com/rust-lang/team/settings/environments

[github-actions]

Dry-run check results

[WARN  sync_team] sync-team is running in dry mode, no changes will be applied.
[INFO  sync_team] synchronizing github
[INFO  sync_team] 💻 Repo Diffs:
    📝 Editing repo 'rust-lang/team':
      Branch Protections:
          main
            Dismiss Stale Reviews: true
            Is admin enforced: true
            Required Approving Review Count: 1
            Requires PR: true
            Required Checks: ["CI"]
            Allowances: []
          master
            Deleting branch protection

[Kobzol]

You should also modify the branch protection in repos/rust-lang/team.toml.

A bunch of repos depend on team through git, but Cargo should be using HEAD instead of master for quite some time, so I think that should be fine.

[marcoieni]

Ok, this is ready to be reviewed by another infra admin 👍
Once this PR is approved I can go through the process of updating the branch