nixos/frigate: allow GPU use for video acceleration

The `render` group is required to acces the graphic cards decoding,
encoding and transcoding capabilities.

It is required for using fancy `ffmpeg.hwaccel-args` values, like
`preset-vaapi`.

nixos/modules/services/video/frigate.nix

@@ -566,7 +566,7 @@ in
 
         User = "frigate";
         Group = "frigate";
-        SupplementaryGroups = optionals withCoral [ "coral" ];
+        SupplementaryGroups = [ "render" ] ++ optionals withCoral [ "coral" ];
 
         UMask = "0027";