Update package.json

see https://github.com/mrdoob/three.js/pull/21509#issuecomment-851946310

package.json

@@ -43,7 +43,8 @@
       "fflate": true,
       "ZSTDDecoder": true,
       "bodymovin": true,
-      "OIMO": true
+      "OIMO": true,
+      "Stats": true
     },
     "rules": {
       "quotes": [