Chore: Update package-lock.json file

[gziolo]

Trac ticket: https://core.trac.wordpress.org/ticket/50420

Follow up for #347.

This PR tries to improve the shape of package-lock.json file and make it stable. The main change is that both dependencies of WordPress packages that use npm aliases are listed as development dependencies: puppeteer and prettier. It looks like npm doesn't handle those aliases properly when they are used as dependencies of dependencies.

This PR also addresses issue raised by @aduth in Gutenberg: WordPress/gutenberg#22417:

As noted at WordPress/gutenberg#21492 (comment) , the version of wp-polyfill shipped in WordPress today is associated with @babel/polyfill@7.4.4. The latest version of @babel/polyfill is 7.8.7. It's assumed this would use a newer version of core-js and thus, polyfills for more new language features in use today in Gutenberg.

Since this is a script handle shipped already with Core, it would inevitably need an upstream patch. It could be done sooner in Gutenberg following the pattern such as in #14400 / Trac#48121.

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This Pull Request is for code review only. Please keep all other discussion in the Trac ticket. Do not merge this Pull Request. See GitHub Pull Requests for Code Review in the Core Handbook for more details.

[gziolo]

I executed npm run dev in the project.

It looks like block.json files should be added to the repository. In addition to that, assets for block editor scripts need to be regenerated.