Update dependency xo to v0.40.1

Author: renovate-bot

package.json

@@ -97,7 +97,7 @@
     "nyc": "15.1.0",
     "power-assert": "1.6.1",
     "regenerator-runtime": "0.13.7",
-    "xo": "^0.33.1"
+    "xo": "0.40.1"
   },
   "files": [
     "lib"