Motivation for this change

I get this error currently when playing a podcast with the app:

podcasts_gtk::widgets::player: gst warning: Warning from element /GstPlayBin:playbin/GstURIDecodeBin:uridecodebin0: There is no codec present that can handle the stream's type.
No decoder available for type 'application/x-id3'.
../gst/playback/gsturidecodebin.c(957): unknown_type_cb (): /GstPlayBin:playbin/GstURIDecodeBin:uridecodebin0

Adding gst-plugins-good to buildInputs fixes this problem.

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS linux)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Determined the impact on package closure size (by running nix path-info -S before and after)
• Ensured that relevant documentation is up to date
• Fits CONTRIBUTING.md.