nixos/akkoma: unpin ffmpeg_5

Their Dockerfile uses Alpine’s ffmpeg package, which is already
on 6. They just invoke the command‐line tool and nothing they do
looks particularly version‐sensitive.

nixos/modules/services/web-apps/akkoma.nix

@@ -452,9 +452,9 @@ in {
 
  extraPackages = mkOption {
  type = with types; listOf package;
- default = with pkgs; [ exiftool ffmpeg_5-headless graphicsmagick-imagemagick-compat ];
- defaultText = literalExpression "with pkgs; [ exiftool graphicsmagick-imagemagick-compat ffmpeg_5-headless ]";
- example = literalExpression "with pkgs; [ exiftool imagemagick ffmpeg_5-full ]";
+ default = with pkgs; [ exiftool ffmpeg-headless graphicsmagick-imagemagick-compat ];
+ defaultText = literalExpression "with pkgs; [ exiftool ffmpeg-headless graphicsmagick-imagemagick-compat ]";
+ example = literalExpression "with pkgs; [ exiftool ffmpeg-full imagemagick ]";
  description = ''
  List of extra packages to include in the executable search path of the service unit.
  These are needed by various configurable components such as: