Bump cdav-library from `051904c` to `c4f7d82`

Bumps [cdav-library](https://github.com/nextcloud/cdav-library) from `051904c` to `c4f7d82`.
- [Release notes](https://github.com/nextcloud/cdav-library/releases)
- [Commits](https://github.com/nextcloud/cdav-library/compare/051904cc2ba254ef8e517932ccaed663e5d2638d...c4f7d8225c2c8cfa5a3d269b3d986698d257dd5d

)

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