typo in opengl-es-support

[imthosea]

https://libgdx.com/wiki/graphics/opengl-es-support

Whenever libGDX is talking about GL20 or GL30, it is in fact referring to OpenGL ES 2.0 and OpenGL ES 3.0. OpenGL ES is an API for rendering 2D and 3D computer graphics. Other popular graphics APIs are for example Direct3D, Metal or Vulcan.

It should be Vulkan

[crykn]

Thanks!