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

This uses `FormulaInstaller#fetch` to recursively fetch dependencies
through the dependency tree and allows `install_dependency` to not
do any fetching.

Fixes #6374.

docs/How-to-Create-and-Maintain-a-Tap: official vendor taps.

Replace ARGV#flags_only with Homebrew.args.flags_only

Replace ARGV#bottle_arch with Homebrew.args.bottle_arch

Cleanup ARGV.include? usage

Livecheck Formula DSL

build(deps): bump rspec-expectations from 3.9.1 to 3.9.2 in /Library/Homebrew

tests.yml: Deploy the Docker image to Docker Hub

Bumps [rspec-expectations](https://github.com/rspec/rspec-expectations) from 3.9.1 to 3.9.2.
- [Release notes](https://github.com/rspec/rspec-expectations/releases)
- [Changelog](https://github.com/rspec/rspec-expectations/blob/master/Changelog.md)
- [Commits](https://github.com/rspec/rspec-expectations/compare/v3.9.1...v3.9.2

)

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

bintray: url encode where needed

cmd/uninstall: fix Array comparison

In #7526 a comparison for `paths` was introduced, but if `paths` is ever
`nil`, this triggers an error.

Coercing the variable to an Array should alleviate this problem, as
`nil.to_a` produces an empty and comparable Array.

Fixes #7540

Signed-off-by: Mike Fiedler <miketheman@gmail.com>

Formula#outdated_kegs: check versions aren't identical.

Remove usage where `Homebrew.args` could be used instead or, due to the
`Homebrew.args` parsing, there was dead code that was never executed
(and no-one complained about not working).

Part of https://github.com/Homebrew/brew/issues/5730

Take two on https://github.com/Homebrew/brew/pull/7490

This removes the coupling on args.formulae before it has been parsed.

Explain our policies around "Official Vendor Taps" and clarify the
formulae naming section.

Inspired by discussion in
https://discourse.brew.sh/t/maintenance-of-formulas-by-vendor/7649/.

Even if the `version_scheme` does not match: we should never try to
`upgrade` (or show `outdated`) for two identical `pkg_version`s.

If this is ever needed: a `revision` bump should be done instead.

Fixes #7507

cmd/uninstall: note etc files that stay around.

grammar fix for How-To-Create-and-Maintain-a-Tap

changing `with you github username` to `with your github username`.

development_tools: fix GCC 10 version detection

compilers: support GCC 10 as a formula