Set `initial_version` to `nil` when `git describe` fails.

Always fetch at least the latest tag.

Bump github-pages from 189 to 190 in /docs

Bumps [github-pages](https://github.com/github/pages-gem) from 189 to 190.
- [Release notes](https://github.com/github/pages-gem/releases)
- [Commits](https://github.com/github/pages-gem/compare/v189...v190

)

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

Per cask/formula `.DS_Store` cleanup

Add cask cleanup and per-formula cache cleanup.

formula_installer: avoid cyclic dependency on Linux

Mac.sdk_path_if_needed tests: stub SDK check

Bump github-pages from 188 to 189 in /docs

Bumps [github-pages](https://github.com/github/pages-gem) from 188 to 189.
- [Release notes](https://github.com/github/pages-gem/releases)
- [Commits](https://github.com/github/pages-gem/compare/v188...v189

)

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

Fix Bottle::Filename.new for taps

Remove executable bit from `ruby.rb` and `prof.rb`.

Fixes:
==> Installing patchelf dependency: patchelf
==> Installing dependencies for patchelf: patchelf
==> Installing patchelf dependency: patchelf
==> Installing dependencies for patchelf: patchelf
==> Installing patchelf dependency: patchelf
==> Installing dependencies for patchelf: patchelf
...

The file name of a bottle should not include the tap.

Mojave: use the CLT SDK where necessary

Use option parser for `brew cleanup`.