Dataset / KVS methods do not accept signature as a param

[barjin]

Since apify/apify-client-js#761, JS client supports use cases like e.g.

await client.dataset(datasetId).listItems({ signature: 'someSignature' });

This allows users to access a specific resource they might not have access to otherwise.

The Python client doesn't accept the signature param in those methods (see e.g. here), which blocks this use case.