Update to SDL2.0.8 including the ninja-fix

conanfile.py

@@ -40,7 +40,7 @@ class ProjectPhoenix(ConanFile):
                 ("glm/0.9.8.5@g-truc/stable"),
                 ("jsonformoderncpp/3.0.1@vthiery/stable"),
                 ("openvr/1.0.12@RWTH-VR/thirdparty"),
-                ("sdl2/2.0.7@bincrafters/stable"),
+                ("sdl2/2.0.8@bincrafters/stable"),
                 ("spdlog/0.16.3@bincrafters/stable"),
                 ("trompeloeil/v29@rollbear/stable"))
     generators = "cmake"