Make Hiitmi run when the screen is off on OnePlus devices

On OnePlus phones, Hiitmi may not be able to run in the background (or when you turn your phone screen off). OnePlus with its OxygenOS has a very aggressive power manager that kills most apps that are running in the background. You can whitelist Hiitmi to make it run in the background, as described here:

https://dontkillmyapp.com/oneplus