chain async compatibility

[hugo082]

It would be helpful to make the chain function compatible with promises.

import { chain, sleep } from 'radashi';

function pause() {
  return async (x: number) => {
    await sleep(100)
    return x + 5;
  }
}

const addTen = chain(
  pause(), // <= ts: Type 'Promise<number>' is not assignable to type 'number'.
  pause(),
)

const ten = await addTen(0)

It should be quite easy via the Awaited<T> typescript type.

[aleclarson]

Probably will need to add a new function for async use cases. No such handling in the current chain implementation.

[barraponto]

This would be particularly useful to create an async filter based on radashi's async map.

[aleclarson]

Hey, just saw this. It's generally an anti-pattern to chain looping functions, for perf reasons. It also makes the code harder to debug, in my experience, versus a simple loop with an if block.

[aleclarson]

Moved to #380