Suggestion: let Deep access methods accept array as key path

[akihikodaki]

Think you have host-to-address map created with Object.create(null):

const store = new Store({
  hostToAddress: Object.create(null)
});

Now, you store IPv address of a domain. If setDeep method accepts an array as a key path:

import { setDeep } from 'svelte-extras';
setDeep.call(store, ['hostToAddress', 'example.com'], '128.66.0.0');

So an array as a key path can include an arbitrary key, and so useful when a key is not sanitized or known to include .. I'd like to see this.