message: Downgrade <formats> tag from required to optional.
diff: @@ -385,6 +385,11 @@ ${enums}
  std::string VulkanHppGenerator::generateFormatTraits() const
  {
  + if ( m_formats.empty() )
  + {
  + return "";
  + }
  +
  const std::string formatTraitsTemplate = R"(
  //=====================
  //=== Format Traits ===
  @@ -14115,12 +14120,12 @@ void VulkanHppGenerator::readRegistry( tinyxml2::XMLElement const * element )
  { "enums", false },
  { "extensions", true },
  { "feature", false },
  - { "formats", true },
  { "platforms", true },
  { "spirvcapabilities", true },
  { "spirvextensions", true },
  { "tags", true },
  - { "types", true } } );
  + { "types", true } },
  + { "formats" } );
  for ( auto child : children )
  {
  const std::string value = child->Value();
  