Update symfony/http-client requirement in /languages/php/sdk
Update symfony/http-client requirement in /languages/php/sdk

Updates the requirements on [symfony/http-client](https://github.com/symfony/http-client) to permit the latest version.
- [Release notes](https://github.com/symfony/http-client/releases)
- [Changelog](https://github.com/symfony/http-client/blob/master/CHANGELOG.md)
- [Commits](https://github.com/symfony/http-client/compare/v4.3.0...v5.1.0)

Signed-off-by: dependabot-preview[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@dependabot.com>
blackfireio/php-sdk