Add Supplemental Materials

Author: PhoneDroid

Data/Index.json

@@ -1390,6 +1390,15 @@
       "curated": true
     }
   ],
+  "Supplemental-Materials" : [
+    {
+      "repository": "https://github.com/FreeCAD/Supplemental-Materials" ,
+      "git_ref": "Latest",
+      "branch_display_name": "Latest",
+      "zip_ur": "https://github.com/FreeCAD/Supplemental-Materials/archive/refs/heads/Latest.zip",
+      "curated": true
+    }
+  ],
   "SvgWorkbench": [
     {
       "repository": "https://github.com/mnesarco/SvgWorkbench",