Update `lerna.json`

lerna.json

@@ -1,15 +1,10 @@
 {
+  "npmClient": "yarn",
   "version": "independent",
   "packages": [
     "website",
     "examples/*",
     "packages/*",
     "packages/@uppy/*",
-    "private/*"
-  ],
-  "command": {
-    "bootstrap": {
-      "npmClientArgs": ["--no-package-lock"]
-    }
-  }
+  ]
 }