Update symfony/yaml requirement from ^4.3 to ^5.0
Update symfony/yaml requirement from ^4.3 to ^5.0

Updates the requirements on [symfony/yaml](https://github.com/symfony/yaml) to permit the latest version.
- [Release notes](https://github.com/symfony/yaml/releases)
- [Changelog](https://github.com/symfony/yaml/blob/master/CHANGELOG.md)
- [Commits](https://github.com/symfony/yaml/compare/v4.3.0...v5.0.0)

Signed-off-by: dependabot-preview[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@dependabot.com>
bavix/flow