Changed libsdl link to https

README.md

@@ -340,7 +340,7 @@ Please take a quick gander at the [contribution guidelines](https://github.com/a
 * [glop](https://github.com/runningwild/glop) - Glop (Game Library Of Power) is a fairly simple cross-platform game library.
 * [go-astar](https://github.com/beefsack/go-astar) - Go implementation of the A* path finding algorithm
 * [go-collada](https://github.com/GlenKelley/go-collada) - Go package for working with the Collada file format.
-* [go-sdl2](https://github.com/veandco/go-sdl2) - Go bindings for the [Simple DirectMedia Layer](http://www.libsdl.org/).
+* [go-sdl2](https://github.com/veandco/go-sdl2) - Go bindings for the [Simple DirectMedia Layer](https://www.libsdl.org/).
 * [go3d](https://github.com/ungerik/go3d) - A performance oriented 2D/3D math package for Go
 * [gonet](https://github.com/xtaci/gonet) - A game server skeleton implemented with golang
 * [Leaf](https://github.com/name5566/leaf) - A lightweight game server framework