Bump cdav-library from `a8e1b3f` to `b7a567e`

Bumps [cdav-library](https://github.com/nextcloud/cdav-library) from `a8e1b3f` to `b7a567e`.
- [Release notes](https://github.com/nextcloud/cdav-library/releases)
- [Commits](https://github.com/nextcloud/cdav-library/compare/a8e1b3fa505ee2e457b2318b16de3795cbca06c3...b7a567e2cff9459634e6801719ad780d4a087bbd

)

---
updated-dependencies:
- dependency-name: cdav-library
  dependency-type: direct:production
...

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