chore: add mention to `develop` branch in CONTRIBUTING
fix: Backport, fixed `found-at` with absolute path
- Refs SassDoc/gulp-sassdoc#2
- Refs abe4fd3
Merge pull request #156 from SassDoc/backport-fix-found-at

Backport, fixed `found-at` with absolute path
Update Changelog
Merge remote-tracking branch 'upstream/master'