Bump cdav-library from `b81b410` to `9069982`

Bumps [cdav-library](https://github.com/nextcloud/cdav-library) from `b81b410` to `9069982`.
- [Release notes](https://github.com/nextcloud/cdav-library/releases)
- [Commits](https://github.com/nextcloud/cdav-library/compare/b81b4107c6af8df619cb8e726401680b60ef0098...906998275c39716601db4348f7f7371d2f154848

)

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