Bump league/climate from 3.5.0 to 3.5.2 in /_backend

Bumps [league/climate](https://github.com/thephpleague/climate) from 3.5.0 to 3.5.2.
- [Release notes](https://github.com/thephpleague/climate/releases)
- [Changelog](https://github.com/thephpleague/climate/blob/master/CHANGELOG.md)
- [Commits](thephpleague/climate@3.5.0...3.5.2)

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