Update guzzlehttp/guzzle requirement in /build/integration

Updates the requirements on [guzzlehttp/guzzle](https://github.com/guzzle/guzzle) to permit the latest version.
- [Release notes](https://github.com/guzzle/guzzle/releases)
- [Changelog](https://github.com/guzzle/guzzle/blob/6.5.3/CHANGELOG.md)
- [Commits](https://github.com/guzzle/guzzle/compare/6.5.2...6.5.3

)

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