build: bump parser from 2.6.3.0 to 2.6.4.0 in /Library/Homebrew

Bumps [parser](https://github.com/whitequark/parser) from 2.6.3.0 to 2.6.4.0.
- [Release notes](https://github.com/whitequark/parser/releases)
- [Changelog](https://github.com/whitequark/parser/blob/master/CHANGELOG.md)
- [Commits](https://github.com/whitequark/parser/compare/v2.6.3.0...v2.6.4.0

)

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