Bumps [socket.io](https://github.com/socketio/socket.io) from 0.9.19 to 2.3.0. - [Release notes](https://github.com/socketio/socket.io/releases) - [Commits](https://github.com/socketio/socket.io/compare/0.9.19...2.3.0) Signed-off-by: dependabot-preview[bot] <support@dependabot.com>