Fix installation with node v10.13.x

[julien]

After cloning alloy-editor with node v10.13.x installing the dependencies fails:

Let's clone the repository

$ cd /tmp
$ git clone git@github.com:liferay/alloy-editor.git
Cloning into 'alloy-editor'...
remote: Enumerating objects: 208, done.
remote: Counting objects: 100% (208/208), done.
remote: Compressing objects: 100% (200/200), done.
remote: Total 31536 (delta 185), reused 19 (delta 8), pack-reused 31328
Receiving objects: 100% (31536/31536), 56.16 MiB | 339.00 KiB/s, done.
Resolving deltas: 100% (24912/24912), done.

Just for reference print out the node and npm version we're using

$ node -v && npm -v
v10.13.0
6.4.1

Let's install the dependencies

$ cd alloy-editor
$ npm i

> fsevents@1.1.2 install /private/tmp/alloy-editor/node_modules/fsevents
> node install

node-pre-gyp ERR! Tried to download(404): https://fsevents-binaries.s3-us-west-2.amazonaws.com/v1.1.2/fse-v1.1.2-node-v64-darwin-x64.tar.gz 
node-pre-gyp ERR! Pre-built binaries not found for fsevents@1.1.2 and node@10.13.0 (node-v64 ABI) (falling back to source compile with node-gyp) 
node-pre-gyp ERR! Tried to download(undefined): https://fsevents-binaries.s3-us-west-2.amazonaws.com/v1.1.2/fse-v1.1.2-node-v64-darwin-x64.tar.gz 
node-pre-gyp ERR! Pre-built binaries not found for fsevents@1.1.2 and node@10.13.0 (node-v64 ABI) (falling back to source compile with node-gyp) 
 

I'm skipping lots of compiler warnings and errors here ... about node-gyp not being able to compile node-sass, and after a while it ends with:

gyp ERR! build error 
gyp ERR! stack Error: `make` failed with exit code: 2
gyp ERR! stack     at ChildProcess.onExit (/private/tmp/alloy-editor/node_modules/node-gyp/lib/build.js:258:23)
gyp ERR! stack     at ChildProcess.emit (events.js:182:13)
gyp ERR! stack     at Process.ChildProcess._handle.onexit (internal/child_process.js:240:12)
gyp ERR! System Darwin 15.6.0
gyp ERR! command "/Users/jc/Documents/node/bin/node" "/private/tmp/alloy-editor/node_modules/node-gyp/bin/node-gyp.js" "rebuild" "--verbose" "--libsass_ext=" "--libsass_cflags=" "--libsass_ldflags=" "--libsass_library="
gyp ERR! cwd /private/tmp/alloy-editor/node_modules/node-sass
gyp ERR! node -v v10.13.0
gyp ERR! node-gyp -v v3.6.2
gyp ERR! not ok 
Build failed with error code: 1
npm WARN optional SKIPPING OPTIONAL DEPENDENCY: fsevents@1.1.2 (node_modules/fsevents):
npm WARN optional SKIPPING OPTIONAL DEPENDENCY: fsevents@1.1.2 install: `node install`
npm WARN optional SKIPPING OPTIONAL DEPENDENCY: Exit status 1

npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! node-sass@4.5.3 postinstall: `node scripts/build.js`
npm ERR! Exit status 1
npm ERR! 
npm ERR! Failed at the node-sass@4.5.3 postinstall script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.

npm ERR! A complete log of this run can be found in:
npm ERR!     /Users/jc/.npm/_logs/2018-11-27T17_10_48_854Z-debug.log

Seeing these errors, it seems that this has to do with node_sass or some related module (gulp-sass? maybe).

We should try to investigate and update these modules.