Fix: koa-views always return the result of the first execution

[nanyuantingfeng]

After the first rendering of html, all request results return the first rendered html;

The reason is that this.koa.use (FN) is called many times, resulting in subsequent requests going through the first registration FN; The closure variables(renderOptions) ref to the first FN`s renderOptions; Results in the return of the same html.

[nanyuantingfeng]

could you deal with it earlier? @jvelo @fabiob @nolazybits @alexproca

[anthrax63]

same problem

[beclass]

thank you But，The warehouse has not been updated