Bump christophwurst/nextcloud from 17.0.2 to 18.0.0

Bumps [christophwurst/nextcloud](https://github.com/ChristophWurst/nextcloud_composer) from 17.0.2 to 18.0.0.
- [Release notes](https://github.com/ChristophWurst/nextcloud_composer/releases)
- [Commits](https://github.com/ChristophWurst/nextcloud_composer/compare/v17.0.2...v18.0.0

)

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