KTX2 textures with single MipMap fail to decode#42

brianpopow merged 3 commits intoSixLabors:mainSixLabors/ImageSharp.Textures:mainfrom

Erik-White:bugfix/ktx2-missing-mipsErik-White/ImageSharp.Textures:bugfix/ktx2-missing-mipsCopy head branch name to clipboard