Wrong error message about color type

[ledyba-z]

cavif/src/img/png/Reader.cpp

Lines 136 to 152 in edf3388

	switch(colorType) {
	case PNG_COLOR_TYPE_GRAY:
	pixelOrder = avif::img::PixelOrder::Mono;
	break;
	case PNG_COLOR_TYPE_RGB:
	case PNG_COLOR_TYPE_PALETTE:
	pixelOrder = avif::img::PixelOrder::RGB;
	break;
	case PNG_COLOR_TYPE_GRAY_ALPHA:
	pixelOrder = avif::img::PixelOrder::MonoA;
	break;
	case PNG_COLOR_TYPE_RGB_ALPHA:
	pixelOrder = avif::img::PixelOrder::RGBA;
	break;
	default:
	throw std::logic_error(fmt::format("Unknown bit depth: {}", bitDepth));
	}

This code checks about color type, not bit-depth.