feat: add utils/async/parallel

[nightknighto]

Resolves #1811 .

Description

This pull request adds a new package utils/async/parallel. Execute functions in parallel, passing the results of all functions to a final callback.

Implemented as discussed in the issue.

Related Issues

• resolves [RFC]: add utils/async/parallel #1811

Questions

Any questions for reviewers of this pull request?

No.

Other

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No.

Checklist

Please ensure the following tasks are completed before submitting this pull request.

• Read, understood, and followed the contributing guidelines.

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@stdlib-js/reviewers

[kgryte]

/stdlib update-copyright-years

[nightknighto]

What changes are needed here?

[nightknighto]

@kgryte @Planeshifter

[kgryte]

LGTM. Thanks, @Deadreyo.

I ended up refactoring a bit. We seem to diverge somewhat across @stdlib/utils/async in terms of whether the function returned by a factory method should accept a done argument. I ended up changing the implementation to require done be provided to the returned function. This made a bit more sense in my mind in terms of how I'd expect the reusable function to be used. One could probably make the argument that we should update series-waterfall similarly.