Fix Issue #40

[daniel-moya]

Bump gulp-sass from 2.3.2 to 3.0.0 😄 (This Fix Issue #40)

Error when making npm install

I solved this by changing in package.json:
"gulp-sass": "^2.3.2"
to
"gulp-sass": "3.0.0",

codecombat/codecombat#4430 (comment)

npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! node-sass@3.13.1 postinstall: `node scripts/build.js`
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the node-sass@3.13.1 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!     C:\Users\yrrod_000\AppData\Roaming\npm-cache\_logs\2019-10-18T09_03_25_525Z-debug.log

[hhaoao]

@damr67 Hello, your PR didn't completely solve the dependency problem, I found that the #36 has been perfectly solved, just did not merge into the master branch.

I find that many people don't find that the problem has been solved, and I'm here to write down how to fetch an inactive request pull, hoping to help those in need.

git clone https://github.com/EmailThis/extension-boilerplate.git
cd .\extension-boilerplate\
git fetch origin pull/36/head:genietim
git merge genietim