Update to Gutenberg 20.6.0

[jsnajdr]

This PR updates the isolated editor to Gutenberg 20.6.0. It's going to be used by P2 and deployed on WP.com.

There are several kinds of changes:

• update the @wordpress/* NPM dependencies to latest versions. From these especially @wordpress/interface is relevant because its code is directly bundled with the isolated editor code.
• update the private API consent string from the "I know..." declaration to "I acknowledge..."
• plenty of CSS class name changes. The isolated editor "recreates" a lot of Post Editor UI by creating divs with Core class names. When these get updated, the ISO editor needs to update them, too. A typical change here is from .edit-post to .editor, for example .edit-post-text-editor to .editor-text-editor. But there are others that were discovered during testing.
• ComplementaryArea no longer has the smallScreenTitle prop and we're removing it here, too (Editor Interface: Remove small header from global styles/plugin sidebar WordPress/gutenberg#64474)
• many CSS overrides need to be subtly changed or removed.

[tyxla]

@jsnajdr it's been a while since I worked with this repo. It would be nice to add some step-by-step testing instructions. Especially considering that we want to build and test on p2 on wpcom.

[mirka]

Repo-wise, which things should we expect to be (still) broken? 😅 I just unblocked the CI failures at a very basic level in #264, but even after that, Storybook/E2E seems to be broken on trunk.

In this PR branch, at least locally:

• I get a ReferenceError: TextDecoder is not defined error for yarn test.
• Storybook does not boot successfully, meaning I can't run E2E tests.

[mirka]

Ok, there's still some kind of error in fork-ts-checker-webpack-plugin/lib/patchTypescript.js, but Storybook and E2E tests seem to be working again after #265.

[jsnajdr]

@tyxla @mirka Apologies for not adding enough context: everything that is in this PR is already deployed on WP.com, in bundled and minified form. Here I'm merely committing the source code changes.

In a sense, the WP.com/P2 deployment is what really matters. The Storybook/e2e failures in this repo are sad, we can spend some timeboxed effort trying to fix them, but at the end of the day they won't prevent us from merging this PR. It contains changes that are already tested and deployed elsewhere, and we can't just throw them away.

[tyxla]

Makes sense @jsnajdr. Do you think we can fix those type errors before merging though?

[jsnajdr]

Do you think we can fix those type errors before merging though?

I hope so! I was able to fix the TextDecoder error, it's a Jest polyfill that we already do in Gutenberg. Then there were SCSS errors from webpack build, and upgrade of the webpack-related packages fixed that. Now the next failure are the type errors...

[jsnajdr]

OK, the TypeScript errors are fixed, now the only thing that fails are the e2e tests.

[tyxla]

OK, the TypeScript errors are fixed, now the only thing that fails are the e2e tests.

I wonder if we should spend some time looking at those, too. The errors seem like something relatively major is missing:

[jsnajdr]

I wonder if we should spend some time looking at those, too. The errors seem like something relatively major is missing:

Oh, something is very wrong with Storybook. I'm trying to upgrade it to the same version as used in Gutenberg.

[jsnajdr]

I upgraded Storybook and now the CI check is all green 🎉 🚀 🕺

[tyxla]

Good to hear! Let's ship this, unless @mirka has any remaining concerns.