Bump xo from 0.20.3 to 0.23.0

Bumps [xo](https://github.com/xojs/xo) from 0.20.3 to 0.23.0.
- [Release notes](https://github.com/xojs/xo/releases)
- [Commits](xojs/xo@v0.20.3...v0.23.0)

Signed-off-by: dependabot[bot] <support@dependabot.com>

package.json

@@ -64,7 +64,7 @@
     "jest": "^23.6.0",
     "jest-junit": "^5.2.0",
     "lerna-changelog": "^0.8.2",
-    "xo": "^0.20.3"
+    "xo": "^0.23.0"
   },
   "jest": {
     "testPathIgnorePatterns": [