fix: Deltabot manufacturer

resources/definitions/deltabot.def.json

@@ -6,7 +6,7 @@
     "metadata": {
         "visible": true,
         "author": "Ultimaker",
-        "manufacturer": "Unknown",
+        "manufacturer": "Danny Lu",
         "category": "Other",
         "file_formats": "text/x-gcode",
         "platform_offset": [ 0, 0, 0]