Upgrade dependencies

[pomek]

Suggested merge commit message (convention)

Internal: Upgraded dev-dependencies. Closes #1203.

---

Additional information

• branch #t/ckeditor5/1203 in all packages should be merged too:
  • Changes in packages: ckeditor/ckeditor5-engine@master...t/ckeditor5/1203
  • Changes in builds: ckeditor/ckeditor5-build-classic@master...t/ckeditor5/1203

mgit fetch && mgit co t/ckeditor5/1203 && mgit co master && mgit merge t/ckeditor5/1203 -- -m 'Internal: Upgraded dependencies. See ckeditor/ckeditor5#1203.' && mgit push

• 2a80aca and 38cec00 need to be reverted before merging

[pomek]

CKEditor 5 and CKEditor 5-dev are fine.

[Reinmar]

Let's not upgrade lerna to version 3 (just yet) due to problems and other options mentioned in #1214.

[pomek]

As you wish but everything seems to work.

[pomek]

Almost everything:

So I'm reverting lerna's changes.

[Reinmar]

I actually tried to upgrade to lerna@3 myself and I knew it caused some issues (although, I stumbled upon something else than you).

[pomek]

lerna@^2 produces the same directories.

Lerna 3 changes some things in configuration (lerna init resolves problems) and on CI I needed to add --no-ci option because of the missing package-lock.json file that caused other problems.

Docs worked, samples in the docs as well. I didn't check the builds.

[pomek]

After reverting lerna's changes, ckeditor5-dev does not require any changes.

[Reinmar]

After reverting lerna's changes, ckeditor5-dev does not require any changes.

There are packages in ckeditor5-dev that we should upgrade now. For instance:

And there are more in ckeditor5-dev that require updates. We should keep them in sync with what we use in ckeditor5 to avoid problems like – postcss-loader works when you run tests, but fails when you try to rebuild the editor (because a different version is used).