Update to OpenGL 4.6 with SPIR-V

[IntegratedQuantum]

OpenGL 4.5 offers direct state access which would make the game more robust against unintended OpenGL state changes.
OpenGL 4.6 offers SPIR-V support which might improve shader optimization(edit: it seems to be slightly worse on my PC, further testing is required) or at least make it least more consistent.

The cost in hardware support is rather small, according to wikipedia the only difference is that Radeon HD 5000 and 6000 Series would no longer be supported which are over 10 years old anyways.

[IntegratedQuantum]

The game already uses OpenGL 4.6