Configure trusted publishing for backtrace-rs and switch its default branch to main

[Kobzol]

No description provided.

[github-actions]

Dry-run check results

[WARN  rust_team::sync] sync-team is running in dry mode, no changes will be applied.
[INFO  rust_team::sync] synchronizing crates-io
[INFO  rust_team::sync] 💻 Trusted Publishing Crate Diffs:
      Setting trusted publishing only option for krate `backtrace` to `true`
[INFO  rust_team::sync] synchronizing github

[INFO  rust_team::sync] 💻 Repo Diffs:

📝 Editing repo 'rust-lang/backtrace-rs':

Rulesets:

Creating 'main'

Include Branches: ["refs/heads/main"]

Required approvals: 1

Deleting 'master'

Environments:

➕ Create: publish

Branches: main

📝 Editing repo 'rust-lang/rustup':

Environments:

🔄 Update: github-pages

Removing branches: gh-pages