Bump socket.io-client from 2.2.0 to 2.3.0 (#244)

Bumps [socket.io-client](https://github.com/Automattic/socket.io-client) from 2.2.0 to 2.3.0.
- [Release notes](https://github.com/Automattic/socket.io-client/releases)
- [Commits](https://github.com/Automattic/socket.io-client/commits)

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

Author: dependabot-preview[bot]

package-lock.json

@@ -18,7 +18,7 @@
     "detect-browser": "^4.8.0",
     "rxjs": "^6.5.3",
     "semver-compare": "^1.0.0",
-    "socket.io-client": "2.2.0"
+    "socket.io-client": "2.3.0"
   },
   "devDependencies": {
     "babel-cli": "^6.26.0",