Fix type error in createDelegation within JS client

[salieflewis]

When implementing the following lines of code as shown in the Delegated example, typescript complains the type of the abilities string array does not match with the expected type.

const abilities = ['upload/add', 'store/add']
const delegation = await client.createDelegation(audience, abilities)

cc: @travis

[alanshaw]

@salieflewis you should be able to do this now to resolve those type errors:

import { asAbilities } from '@web3-storage/w3up-client'

const abilities = asAbilities(['upload/add', 'store/add'])
const delegation = await client.createDelegation(audience, abilities)

Shout if you find it not working properly.