Require SDL2 2.0.16 as a minimum
This prevents some really confusing CMake errors because packages <2.0.16 do not ship with the SDL2::SDL2 target.
See https://github.com/libsdl-org/SDL/commit/fe6f62e6ce6cdf2583b513a4b39ec4f3d93dec87
This prevents some really confusing CMake errors because packages <2.0.16 do not ship with the SDL2::SDL2 target.
See https://github.com/libsdl-org/SDL/commit/fe6f62e6ce6cdf2583b513a4b39ec4f3d93dec87