Update obsolete code of index.js of example "online"

[leeli0]

online package is obsolete, doesn't work with the latest redis package any more. The way to connect to redis server also is also need to be changed.

[wesleytodd]

Honestly I think I am of the opinion that we should delete all examples that rely on external packages. This is too much of a risk for us to be promoting if the express project doesn't own the package. This is a great target for a malicious attacker. I am going to bring this one up with the rest of the @expressjs/express-tc to get a feel for folks opinions, but my vote is we remove this example entirely.

[ctcpip]

technically, online is a tjholowaychuk package, so... 😁