Split out prepare_patches and fetch_patches methods.

docs/New-Maintainer-Checklist: clarify ops can get owner.

The new `fetch_patches` method wasn't exclusively fetching so shouldn't
have been skipped when it was.

Fixes #7558.

This is needed for Bo98 to get access to GitHub Actions shared runners.

Merge pull request #7561 from Homebrew/dependabot/bundler/Library/Homebrew/mime-types-data-3.2020.0512

build(deps): bump mime-types-data from 3.2020.0425 to 3.2020.0512 in /Library/Homebrew

formula JSON: include URLs for non-bottled formulae

Bumps [mime-types-data](https://github.com/mime-types/mime-types-data) from 3.2020.0425 to 3.2020.0512.
- [Release notes](https://github.com/mime-types/mime-types-data/releases)
- [Changelog](https://github.com/mime-types/mime-types-data/blob/master/History.md)
- [Commits](https://github.com/mime-types/mime-types-data/compare/v3.2020.0425...v3.2020.0512

)

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

Fix formatting issue in Formula Cookbook

workflows/tests: fix for pre-installed Linuxbrew

Fetch (all) resources when building from source

Also:
- when `brew test` or `brew postinstall` is run allow `Resource#stage`
  to fetch the resource.
- make `Formula#fetch` and `Resource#fetch` fetch external patches too.

Follow-up from #7549 and #7546.

formula_installer: ignore dependencies when fetching.

utils/fork: check for inner exception command.

Whenever you are fetching a dependency you only care about fetching that
specific dependency and not all the dependencies of that dependency.

Unlike installing, dependencies can be fetched in any order and have no
"chains" between them.

If it's not present then `ErrorDuringExecution` and `BuildError` don't
work correctly so better to fall back to a default `RuntimeError`.

build(deps): bump rubocop from 0.82.0 to 0.83.0 in /Library/Homebrew

Document how to use test fixtures

This crashes `brew style`.

Bumps [rubocop](https://github.com/rubocop-hq/rubocop) from 0.82.0 to 0.83.0.
- [Release notes](https://github.com/rubocop-hq/rubocop/releases)
- [Changelog](https://github.com/rubocop-hq/rubocop/blob/master/CHANGELOG.md)
- [Commits](https://github.com/rubocop-hq/rubocop/compare/v0.82.0...v0.83.0

)

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

resource: restore fetch in stage

Fixes #7546.

brew.sh: check versions of proper cURL and Git

Co-authored-by: Mike McQuaid <mike@mikemcquaid.com>

Co-authored-by: Mike McQuaid <mike@mikemcquaid.com>

Fetch formula resources before unlinking during upgrade.

workflows: fix docker hub pushing