Bump mikey179/vfsstream from 1.6.7 to 1.6.8
Bump mikey179/vfsstream from 1.6.7 to 1.6.8

Bumps [mikey179/vfsstream](https://github.com/bovigo/vfsStream) from 1.6.7 to 1.6.8.
- [Release notes](https://github.com/bovigo/vfsStream/releases)
- [Changelog](https://github.com/bovigo/vfsStream/blob/v1.6.8/CHANGELOG.md)
- [Commits](https://github.com/bovigo/vfsStream/compare/v1.6.7...v1.6.8)

Signed-off-by: dependabot-preview[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@dependabot.com>
kranack/PHP-Tools