[headroom] mark as conflicting with npm (DefinitelyTyped#74657)

Author: jakebailey

types/headroom/package.json

@@ -2,7 +2,7 @@
     "private": true,
     "name": "@types/headroom",
     "version": "0.12.9999",
-    "nonNpm": true,
+    "nonNpm": "conflict",
     "nonNpmDescription": "headroom",
     "projects": [
         "http://wicky.nillia.ms/headroom.js/"