This updates the Prowlarr plugin so that it is compatible with [Buildarr v0.5.0](https://buildarr.github.io/release-notes/#v050-2023-04-16).
Other changes to the Prowlarr plugin for this release include:
* Rename the Freebox download client `priority` attribute to `client_priority` (same as other download client types), as it was shadowing the Prowlarr-oriented `priority` attribute (common to all download clients), and giving incorrect values for both attributes
* Improve support for deleting resources with `delete_unmanaged`, by using the new `delete_remote` API function
* Remove the `prowlarr.tags.delete_unused` attribute (for deleting Prowlarr tags not used in Buildarr), as it was unimplemented and Prowlarr automatically cleans up unused tags anyway
Changed
* Update plugin to newer Buildarr API standards ([10](https://github.com/buildarr/buildarr-prowlarr/pull/10))