user/supertux: Add missing zlib-dev dependency

user/supertux/APKBUILD

@@ -8,7 +8,7 @@ url="https://www.supertux.org/"
 arch="all"
 license="GPL-3.0+"
 depends=""
-makedepends="boost-dev cmake curl-dev glew-dev libogg-dev libvorbis-dev
+makedepends="boost-dev cmake curl-dev glew-dev libogg-dev libvorbis-dev zlib-dev
 	mesa-dev openal-soft-dev physfs-dev sdl2-dev sdl2_image-dev doxygen"
 subpackages="$pkgname-doc"
 source="https://github.com/SuperTux/supertux/releases/download/v$pkgver/SuperTux-v$pkgver-Source.tar.gz"