Using TEXCOORD_0 or COLOR_0 as morph targets results in MESH_PRIMITIVE_INVALID_ATTRIBUTE error

[UX3D-haertl]

The spec specifically allows morphing of texcoord and color attributes. Link It is also supported by sample viewer. The description in mesh.primitive.schema.json is misleading. I will also raise an issue about it in the glTF repo.

[stephomi]

+1 many people are still using the validator. Made a PR a while ago but it wasn't accepted https://github.com/KhronosGroup/glTF-Validator/pull/193