message: gltfpack: Fixed missing mime_type
diff: @@ -567,6 +567,10 @@ void writeImage(std::string& json, std::vector<BufferView>& views, const cgltf_i
  mime_type = inferMimeType(image.uri);
  }
  + else if (image.uri)
  + {
  + mime_type = image.mime_type ? image.mime_type : inferMimeType(image.uri);
  + }
  if (!img_data.empty())
  {
  