Update package name for SUSE

The devel package has this name in Tumbleweed as well as in the "games" extra repository in Leap

see the list of built packages near the bottom of this build log:
https://build.opensuse.org/package/live_build_log/openSUSE:Factory/SDL2_ttf/standard/x86_64

Author: tuohy

packages/conf-sdl2-ttf/conf-sdl2-ttf.1/opam

@@ -11,7 +11,7 @@ depexts: [
   ["libsdl2-ttf-dev"] {os-family = "debian"}
   ["libsdl2-ttf-dev"] {os-family = "ubuntu"}
   ["libsdl2_ttf-devel"] {os-family = "mageia"}
-  ["libSDL2_ttf-devel"] {os-family = "suse" | os-family = "opensuse"}
+  ["SDL2_ttf-devel"] {os-family = "suse" | os-family = "opensuse"}
   ["SDL2_ttf-devel"] {os-distribution = "fedora"}
   # oraclelinux does not seem to have sdl2-ttf
   ["epel-release" "SDL2_ttf-devel"] {os-distribution = "centos"}