Add `delay` effect

I keep copying+pasting the delay effect between my projects. Don’t you think it would be a good candidate to be included in redux-saga?

I have also enhanced the signature of the function to yield to true instead of undefined:

function delay(ms) {
  return new Promise(resolve => setTimeout(() => resolve(true), ms))
} 

Then you could easily check for timeouts in race

const { timeout, otherCall } = yield race({
  timeout: call(delay, 5000),
  otherCall: call(asyncFunc, ...)
})

[chenxsan]

@Anahkiasen I think it’s import {delay} from 'redux-saga'.

[yelouafi]

adding a delay util function could make sens. But adding a new effect here is irrelevant here since this is just an alias for a call effect. I prefer to keep the core small and focused