Bump socket.io-client from 2.1.1 to 2.2.0

Bumps [socket.io-client](https://github.com/Automattic/socket.io-client) from 2.1.1 to 2.2.0.
- [Release notes](https://github.com/Automattic/socket.io-client/releases)
- [Commits](socketio/socket.io-client@2.1.1...2.2.0)

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot-support

package-lock.json

@@ -18,7 +18,7 @@
     "detect-browser": "^4.0.3",
     "rxjs": "^6.3.3",
     "semver-compare": "^1.0.0",
-    "socket.io-client": "2.1.1"
+    "socket.io-client": "2.2.0"
   },
   "devDependencies": {
     "babel-cli": "^6.26.0",