Bump christophwurst/nextcloud from 16.0.0-RC1 to 16.0.0

Bumps [christophwurst/nextcloud](https://github.com/ChristophWurst/nextcloud_composer) from 16.0.0-RC1 to 16.0.0.
- [Release notes](https://github.com/ChristophWurst/nextcloud_composer/releases)
- [Commits](https://github.com/ChristophWurst/nextcloud_composer/compare/v16.0.0-RC1...v16.0.0

)

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