Bumps [symfony/http-kernel](https://github.com/symfony/http-kernel) from 5.1.2 to 5.1.8. - [Release notes](https://github.com/symfony/http-kernel/releases) - [Changelog](https://github.com/symfony/http-kernel/blob/5.x/CHANGELOG.md) - [Commits](https://github.com/symfony/http-kernel/compare/v5.1.2...v5.1.8) Signed-off-by: dependabot[bot] <support@github.com>