Fix Skia not rendering with some Radeon drivers on Windows

Sometimes Radon drivers report on Windows erroneously that it supports
GL_NV_framebuffer_blit as extension but when looking up
glBlitFramebufferNV via getProcAddress it returns a null pointer.

The issue goes away when bumping the GLES version. GLES 2.0 was released
in 2003 and 3.0 in 2012. Practically everyone supports it nowadays (even
Safari), so that's the easiest solution for the Skia renderer.

internal/renderers/skia/opengl_surface.rs

@@ -267,7 +267,7 @@ impl OpenGLSurface {
 
                 let gles_context_attributes = ContextAttributesBuilder::new()
                     .with_context_api(ContextApi::Gles(Some(glutin::context::Version {
-                        major: 2,
+                        major: 3,
                         minor: 0,
                     })))
                     .build(Some(_window_handle.raw_window_handle()));