Update README.md

[xie-qianyue]

figure out that the exercises are only verified under koa 1, but not koa 2.

[hemanth]

Any specific issues you noticed?

[xie-qianyue]

@hemanth yes, please see this issue. I'm not sure whether it concerns the version, but as @dead-horse says, maybe it's the version problem.

[hemanth]

Hmm, rather than updating the readme, it's better we migrate to 2.0 it be nice if you could modify the text to something like:

Note that the exercises of kick-off are only verified under koa 1, but NOT koa 2. Meanwhile we are migrating to kao 2 and you can also take part in it.

[tejasmanohar]

👍 for what @hemanth said since we do want to have Koa 2 stuff eventually too :)

[xie-qianyue]

@hemanth I have modified the READ ME as you proposed. I will test the exercises under koa 2. If I find something wrong, I will create the issue.

[hemanth]

@xie-qianyue Cool, thanks.

Please have a single issue with checklists.