Ubuntu Linux - Dota 2 - Graphics card doesn't support OpenGL 3.1

Not knowing your entire system, it's difficult to help. Dota 2 on Ubuntu has some issues, and I'm not sure your GPU can handle it well - can you perhaps elaborate your system?

I would first and foremost go to launch options and force directX. Either run -dx9 (for directx 9) or -dx11(for directx11) to remove the OpenGL option.

I am, however, afraid you're on a laptop that does not have a good enough GPU(and likely other components) to run the game properly.

Try running steam --reset as suggested here

No, you can't run the game with an older version of OpenGL API. Nor can you "upgrade" your software to add OpenGL 3.1 (or newer) support, unless your hardware itself supports it, and newer drivers are available which enable it.

You need to find the detailed specs of your GPU (or CPU if using internal graphics on Intel/AMD) to see if it supports the version of OpenGL, and then if so, make sure you are using the correct drivers for your GPU. Depending on the GPU you're using, and version of Ubuntu you're on, you may need to switch to different drivers.