Add readme note about @koa/router

[christianbundy]

It's very confusing that koa-router on npm has new versions published by @niftylettuce that aren't reflected in this readme. It would be great to have at least a note in the readme explaining what's going on.

[niftylettuce]

Not going to happen. GitHub refused to give me access and the author is unresponsive after a year.

…

On March 23, 2020 10:47:54 PM UTC, Christian Bundy ***@***.***> wrote: It's very confusing that koa-router on npm has new versions published by @niftylettuce that aren't reflected in this readme. It would be great to have at least a note in the readme explaining what's going on. -- You are receiving this because you were mentioned. Reply to this email directly or view it on GitHub: #523

-- Sent from my Android device with K-9 Mail. Please excuse my brevity.

[marklai1998]

or at least pin some issue?
I think there still a lot of confusion between the two

[sombriks]

so let's make this issue here more famous, even doing the opposite: adda deprecation notice about this repo on https://github.com/koajs/router