Just to be clear. The string
argument in new Material(string)
is whole shaderlab code. Not a shader name.
Unity 5.2 is dropping support for non-precompiled shaders (at least here) for the sake of compatiblity with some consoles or something, so compiling shaderlab code at runtime like that won't work anymore.
But Spine-Unity doesn't do that anywhere, so there's nothing to worry about.