End of Linux Client support

As announced in a previous blog post, update 2.1.3 will mark the end of Linux client support. We will instead pivot towards supporting Proton, Valve's compatibility layer for Windows games running on Linux, and focus on fixing any bugs that manifest with it. Proton's Vulkan-based backend renderer, DXVK, should have better performance and fewer issues for Linux users.

This wiki page serves as a guide on how to migrate to Proton to continue playing.