Upgrade broccoli-persistent-filter to v3

[nlfurniss]

Upgrade broccoli-persistent-filter for increased performance.

Also

• moved Node support to the current maintenance version
• fixed eslint errors

[stefanpenner]

Questions:

• this is a breaking change, so I assume it is ok if I release this with a major version bump?
• would this benefit from parallel builds as well?

[nlfurniss]

• this is a breaking change, so I assume it is ok if I release this with a major version bump?

yup!

• would this benefit from parallel builds as well?

I do not know, but googling ember cli parallel build didn't yield anything useful...

[stefanpenner]

would this benefit from parallel builds as well?
I do not know, but googling ember cli parallel build didn't yield anything useful...

Basically, if each "processString" in a broccoli-persisitent filter subclass, is entirely independent of the other, and if each one is CPU limited and sufficiently slow, we can actually run them in parallel via node worker_threads or sub-processes.

This doesn't block this PR at all, but I wanted to see if this is important as it could yield an improvement if it is common for autoprefixer to be given many individual files, and the processing itself is CPU bound.

If that sounds like a fit, it may be worth a future effort to make this part parallel. Let me know.

[stefanpenner]

this is a breaking change, so I assume it is ok if I release this with a major version bump?
yup!

Thanks for the confirmation.