Upgrade node-sass to 4.12

[desrosj]

Running npm install currently fails when running the latest version of Node (12.2.0 with NPM 6.9.0).

Core currently requires ~4.11.0 of node-sass, but only 4.12+ ​supports Node 12.2.0.

[desrosj]

​Accompanying Gutenberg PR.

[aduth]

From the proposed 47257.diff​, should I expect it would include corresponding updates to the package-lock.json file as well?

[desrosj]

@aduth Ah, yes. Sorry, I missed including the package-lock.json changes in the previous patch. 47257.2.diff​ should have everything.

[aduth]

@desrosj Applying the revised patch and running npm install, I see that it produces a different result in package-lock.json.

Which versions of Node and NPM are you running? I'm not familiar with what's stipulated, but I've tried with both the `engines` versions (Node 10.13.0, npm 6.1.0) and ​Gutenberg recommendations (Node 10.15.3, npm 6.9.0).

[desrosj]

I am also seeing something different now when I try to reproduce 47257.2.diff​.

I am using Node 10.15.3 (npm 6.4.1). I believe my steps were:

• Change version to ~4.12.0.
• Run npm install.

47257.3.diff​ has what I see now.

[aduth]

I think 47257.2.diff​ is the most reasonable patch. Testing again (with latest NPM 6.9.0), I both see (a) no local changes after running npm install and (b) an identical patch when installing from 47257.diff​ (i.e. without the package-lock.json changes). The changes themselves also seem reasonable vs. 47257.3.diff​ where we shouldn't want to flip-flop between optional and dev properties of unaffected modules.

Related discussion in #core-js Slack earlier today, about specific NPM version to be using: ​https://wordpress.slack.com/archives/C5UNMSU4R/p1558022288363200

[netweb]

Replying to aduth:

I think 47257.2.diff​ is the most reasonable patch.

Agreed, 47257.2.diff​ looks good to me, untested, but still 👌

[desrosj]

In 45321:

Build/Test Tools: Upgrade node-sass to 4.12.0.

node-sass 4.12 adds support for Node 12. This will prevent errors for anyone running Node 12 locally instead of the LTS version (currently 10.15.3).

Props desrosj, aduth, netweb.
Fixes #47257.

[desrosj]

I'm going to leave this in trunk (5.3) and not backport for now. It is not urgent. If there are more reports of users having issues testing 5.2, we can reconsider.