message: Add minimum OpenGL version to readme
  Fixes
diff: @@ -47,6 +47,10 @@ Prebuilt binaries for macOS and Windows can also be downloaded from the
  For everyone else, the detailed instructions to install Alacritty can be found
  [here](INSTALL.md).
  +Since Alacritty uses OpenGL to render the terminal content on all platforms, it
  +is currently not possible to run Alacritty without at support for at least
  +OpenGL 3.3.
  +
  ## Configuration
  You can find the default configuration file with documentation for all available
  