Ports: Fix MilkyTracker install script

Author: https://github.com/jakewestrip
Commit: 1ce70bb418
Pull-request: https://github.com/SerenityOS/serenity/pull/6686
Reviewed-by: https://github.com/linusg

Ports/milkytracker/package.sh

@@ -14,3 +14,7 @@ launcher_command=/usr/local/bin/milkytracker
 configure() {
     run cmake $configopts
 }
+
+install() {
+    run make install
+}