Add Radarr V5 support

[Callum027]

Add supported for the recently released Radarr V5. Unlike the transition to Sonarr V3 to V4, this release is relatively minor from an API perspective, so backwards compatibility with Radarr V4 should be able to be maintained.

• [x] Add version to the secrets metadata
• [x] Add support for external authentication
  • Keep none authentication support for Radarr V4 compatibility
• [ ] Add support for Release Profiles (V5 onwards)
• [ ] Add support for indexer restrictions (V4 only, not yet implemented)
• [x] Add relevant notes for V4 and V5 features

[Callum027]

Tags:

• https://github.com/Radarr/Radarr/releases/tag/v5.0.0.7952
• https://github.com/Radarr/Radarr/releases/tag/v5.0.1.7993
• https://github.com/Radarr/Radarr/releases/tag/v5.0.2.8103
• https://github.com/Radarr/Radarr/releases/tag/v5.0.3.8107
• https://github.com/Radarr/Radarr/releases/tag/v5.0.3.8127

Milestone:

• https://github.com/Radarr/Radarr/milestone/14
• https://github.com/Radarr/Radarr/milestone/14?closed=1

[Callum027]

I think I've listed all the relevant major changes for Buildarr.

[Callum027]

https://github.com/buildarr/buildarr-radarr/pull/16

[Callum027]

Related issue: https://github.com/buildarr/buildarr-radarr/issues/20