Add and vendor `rubocop-sorbet` and `sorbet-runtime-stub`.

sorbet: Update RBI files and prune files.yaml.

Autogenerated by [a scheduled GitHub Action](https://github.com/Homebrew/brew/blob/master/.github/workflows/sorbet.yml).

build(deps-dev): bump github-pages from 208 to 209 in /docs

build(deps): bump codecov from 0.2.11 to 0.2.12 in /Library/Homebrew

Bumps [codecov](https://github.com/codecov/codecov-ruby) from 0.2.11 to 0.2.12.
- [Release notes](https://github.com/codecov/codecov-ruby/releases)
- [Changelog](https://github.com/codecov/codecov-ruby/blob/master/CHANGELOG.md)
- [Commits](https://github.com/codecov/codecov-ruby/compare/v0.2.11...v0.2.12

)

Signed-off-by: dependabot[bot] <support@github.com>

Bumps [github-pages](https://github.com/github/pages-gem) from 208 to 209.
- [Release notes](https://github.com/github/pages-gem/releases)
- [Commits](https://github.com/github/pages-gem/compare/v208...v209

)

Signed-off-by: dependabot[bot] <support@github.com>

Fix `dependabot.yml`.

audit: allow Linux checking Homebrew dependencies.

This applies to linuxbrew-core rather than Linux, really.

audit: check versioned dependency conflicts.

We don't want to have a formula depending on e.g. both `python@3.8` and
`python@3.9` in the same dependency tree (generally).

As this isn't a blanket rule: add an allowlist with the expectation that
we'll need to use it.

Update vendored gems.

Reduce shallow clone usage