Build: Make lerna a dependency rather than a devDependency

[gziolo]

Description

Closes #6718 raised by @nerrad.

I guess it's a temporary solution until we have all packages published.

In general, you shouldn't need to do it. You can double check looking at package.json files from Babel, Jest or create-react-app.

How has this been tested?

npm i still works.

[gziolo]

Lerna has impressive number of dependencies :)

[nerrad]

Thanks for doing this, I can confirm it fixes the issue I reported. I'm curious what this statement means though:

You can double check looking at package.json files from Babel, Jest or create-react-app

It seems like something that would be handy knowledge to have.

[ntwb]

@nerrad Once we have all the things published to https://www.npmjs.com/org/wordpressand working as expected we should be able to remove Lerna from dependencies back to devDependencies as you will be able to inspect the various package.json files and only require the packages you need to require rather than all of Gutenberg as is the case for you right now.

p.s And we will update the docs on how to do this then also

[gziolo]

Yes, what @ntwb explained, thanks 🙇

[nerrad]

Ahh gotcha, I was already aware of that but didn't realize that's what was being referred to. Thanks for clarifying 👍