Bump cdav-library from `4f198b6` to `1cefd17`

Bumps [cdav-library](https://github.com/nextcloud/cdav-library) from `4f198b6` to `1cefd17`.
- [Release notes](https://github.com/nextcloud/cdav-library/releases)
- [Commits](https://github.com/nextcloud/cdav-library/compare/4f198b64dcc5f8ed7c152b4a2bc5b8de1ed305c8...1cefd176749fc7a75e47b98b50bd0140393f147a

)

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