chore(deps): update dependency xo to v0.20.2

Author: renovate-bot

package.json

@@ -109,7 +109,7 @@
     "typescript": "2.7.1",
     "typescript-styled-plugin": "0.4.0",
     "webpack-bundle-analyzer": "2.10.0",
-    "xo": "0.18.2"
+    "xo": "0.20.2"
   },
   "keywords": [],
   "contributors": [