Update linuxserver/prowlarr Docker tag to v1.21.2

[renovate[bot]]

This PR contains the following updates:

Package	Update	Change
linuxserver/prowlarr (source)	patch	1.21.0-develop -> 1.21.2-develop

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Release Notes

linuxserver/docker-prowlarr (linuxserver/prowlarr)

### [`v1.21.2`](https://togithub.com/linuxserver/docker-prowlarr/compare/1.20.1.4603-ls78...nightly-1.21.2.4632-ls30)

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Configuration

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