Correct SDL version.

CMakeLists.txt

@@ -136,7 +136,7 @@ set(MEGA_LIBOGG_VER "1.3.1")
 set(MEGA_LIBVORBIS_VER "1.3.3")
 set(MEGA_MPG123_VER "1.15.3")
 set(MEGA_FREETYPE_VER "2.5.0.1")
-set(MEGA_SDL2_VER "2.0.1-3742e768b536")
+set(MEGA_SDL2_VER "2.0.3")
 set(MEGA_SDL2_IMAGE_VER "2.0.0")
 set(MEGA_OPENAL_VER "1.15.1-29e0af5ef052")
 set(MEGA_JASPER_VER "1.900.1")