update the version of gulp-sass

[carpecodeum]

Describe the bug
the current version of gulp-sass is causing errors on setting up on OSX
"Node Sass does not yet support your current environment: OS X 64-bit with Unsupported runtime (64)"

To Reproduce
Steps to reproduce the behavior:

1. Do NPM install
2. See error

Expected behavior
the error should not have been there and the project should have set up just fine

Desktop (please complete the following information):

• OS: [e.g. iOS] OSX
• Browser [e.g. chrome, safari]CHROME

Additional context
upgrading to gulp-sass 3.1.0 solves the issue