Set CMP0072 to NEW to prefer GLVND over legacy OpenGL modules

[SunBlack]

Fixes #3065.

I tested it with my Ubuntu VM and there I still get a valid OpenGL output, so I hope value NEW of CMP0072 doesn't break anything. (maybe a Mac OS user can test this PR before merging)

[taketwo]

LGTM, but I don't have any system with 3.11 to test.

[SergioRAgostinho]

Tried it on OS X High Sierra with CMake 3.12. Unsurprisingly, managed to compile things. Actually our OS X CI is pretty modern in terms of software tools due to homebrew's distribution model.

This is good to go imo.

[SergioRAgostinho]

Spoke too soon, as usual.

$ bin/pcl_sim_test_simple ../test/colored_cloud.pcd 
Manually generate a simulated RGB-D point cloud using pcl::simulation. For more information, use: bin/pcl_sim_test_simple -h
Status: Using GLEW 2.1.0
OpenGL 2.0 supported
GL_MAX_VIEWPORTS: 33371
SumReduce: levels: 4
Failed loading vertex shader
$

But this is happening even prior to your PR, so there's a problem already for who knows how long.