Missing interval property in ora

[leonsilicon]

Hi, firstly, sorry for opening this issue in the wrong repository, but I couldn't open a PR over at https://github.com/sindresorhus/ora since it gives the following message:

An owner of this repository has limited the ability to open a pull request to users that have contributed to this repository in the past.

I was hoping the interval property could be added to the Ora interface since the property seems to exist and works fine in JavaScript: main...leonzalion:main

As always, thanks for your open-source work!

[sindresorhus]

What's the use-case for changing the interval while the spinner is running?

[leonsilicon]

Oh, I wasn't planning on changing it, just reading the value; I was creating a plugin for Inquirer that needed the spinner's frame to be manually rendered to the screen, and I based it off the code from here: https://github.com/SBoudrias/Inquirer.js/pull/1002/files#diff-d15f352de0d8de4937a7e8f493b69295240a480833cc7331155291bcf7aa8005R50 which reads from the interval property on the ora spinner.