🎉 Add support for ULMO format (LZMA compression) (#220)

Author: zorgiepoo

README.md

@@ -67,6 +67,7 @@ the JSON file's path.
     - `UDZO` - UDIF zlib-compressed image
     - `UDBZ` - UDIF bzip2-compressed image (OS X 10.4+ only)
     - `ULFO` - UDIF lzfse-compressed image (OS X 10.11+ only)
+    - `ULMO` - UDIF lzma-compressed image (macOS 10.15+ only)
 - `contents` (array[object], required) - This is the contents of your DMG.
     - `x` (number, required) - X position relative to icon center
     - `y` (number, required) - Y position relative to icon center

schema.json

@@ -62,6 +62,7 @@
         "UDCO",
         "UDZO",
         "ULFO",
+        "ULMO",
         "UDBZ"
       ]
     },