bottle: add tests for json merging

- Extract the json reading from the json merging: it makes the code hard to understand.
This helps for the separation of concerns: the jsons are read in one method;
and merged in a second one
- Added a first test to check the merge function

No change in behaviour was done, this change is just there to increase code coverage
and to prepare for #9315

software_spec: make bottle sorting stable.

cmd/update: improve shallow clone message.

dev-cmd/dispatch-build-bottle: remove testing code.

As `:arm64_big_sur` and `:big_sur` equated to the same version: their
sorting was not consistent. Instead, suffix the tag and use that for
sorting so `:big_sur` is always before `:arm64_big_sur`.

build(deps-dev): bump html-proofer from 3.17.3 to 3.17.4 in /docs

build(deps): bump sorbet from 0.5.6130 to 0.5.6134 in /Library/Homebrew

diagnostic: don't complain about creatable directories that don't exist.

This was accidentally merged in https://github.com/Homebrew/brew/pull/9444.

Bumps [sorbet](https://github.com/sorbet/sorbet) from 0.5.6130 to 0.5.6134.
- [Release notes](https://github.com/sorbet/sorbet/releases)
- [Commits](https://github.com/sorbet/sorbet/commits

)

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

Bumps [html-proofer](https://github.com/gjtorikian/html-proofer) from 3.17.3 to 3.17.4.
- [Release notes](https://github.com/gjtorikian/html-proofer/releases)
- [Commits](https://github.com/gjtorikian/html-proofer/compare/v3.17.3...v3.17.4

)

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

If you can write to `HOMEBREW_PREFIX` (which isn't the case for
`/usr/local` on newer macOSs) then don't complain about these
directories not existing.

dev-cmd/dispatch-build-bottle: set ARM labels.

Set the label properly for ARM.

Tested with inputs `11-arm` and `arm64_big_sur`.

Fixes https://github.com/Homebrew/brew/issues/9434

Fix `:arm64_big_sur` bottle ordering.

brew.sh: don't allow system Ruby on Catalina.

livecheck: add GithubLatest strategy

This wasn't being parsed correctly so was being put below the Linux
bottle which is less readable, less intuitive and will cause a bunch
of merge conflicts.

It's (far) too broken for our purposes.

Fixes https://github.com/Homebrew/brew/issues/9410

workflows/tests: consolidate macOS tests.

git_extensions: refactor and delete redundant functions