Give priority to GLFW_OPENGL_ES_API over GLFW_OPENGL_API in window_glfw.c

[spedagadi]

Just a suggestion - On ARM boards, the rendering is slow with OpenGL but OpenGL ES is much better and realtime to some extent. In plplay's window_glfw.c, this array https://github.com/haasn/libplacebo/blob/1fd3c7bde7b943fe8985c893310b5269a09b46c5/demos/window_glfw.c#L199 could be adjusted such that the window creation tries all OpenGL ES options first and then tries OpenGL if unsuccessful.