Change sample to show usage of --app-drop-link
Change sample to show usage of --app-drop-link

The sample hadn't been updated along with the script when --app-drop-link was added.
digitalreasoning/create-dmg,andrey-str/create-dmg,strukturag/create-dmg,jmara/yoursway-create-dmg,heavilessrose/create-dmg,strukturag/create-dmg,mrpau/create-dmg,andreyvit/create-dmg,heavilessrose/create-dmg,andreyvit/create-dmg,heavilessrose/create-dmg,digitalreasoning/create-dmg,digitalreasoning/create-dmg,mrpau/create-dmg,andrey-str/create-dmg,andreyvit/create-dmg,jmara/yoursway-create-dmg,andrey-str/create-dmg,strukturag/create-dmg,jmara/yoursway-create-dmg,mrpau/create-dmg