Update all the devdependencies

Summary:
Based on rINFRAWWW
Reference: https://www.npmjs.com

The imagemin process now handle SVG, GIF and PNG. For JPEG, mozjpeg
supersedes jpegtran.

Dart Saas supersedes node-sass, as the reference SCSS implementation.

To make YAML loading safer, optional types like regexps
are extracted to a separate js-yaml-js-types package.

Signed-off-by: Sébastien Santoro <dereckson@espace-win.org>

Test Plan:
Build a test site
make test

Reviewers: dereckson, DorianWinty

Reviewed By: dereckson, DorianWinty

Differential Revision: https://devcentral.nasqueron.org/D3588