Adding Promise support to text option?

[ClementParis016]

Considering a reasonable amount of people want to perform asynchronous operations before a clipboard action, I think adding Promise support to the text option would be nice.

For example, you may want to call an API when clicking a button and use its response data as the value to be copied.

As far as I could explore the code, it doesn't seem to be such a big change to allow both a function or a promise to be passed as an argument.

What do you think @zenorocha ? I could start working on a PR if that feels right.

[zenorocha]

Hey @ClementParis016,

I'm open to this change. Here's a proposal for it #517. Let me know what you think and if you're able to help.

Thanks for the suggestion!