chore(deps): Update Sass, SLDS and related deps (#65)

- copy edits
- remove ruby for dart Sass
- update gulp-sass
- update gulp-load-plugins
- update slds in the lock file

Author: Dottenpixel

README.md

@@ -99,7 +99,7 @@ git checkout master
 git pull origin master
 ```
 
-Or, in GitHub Desktop, click `Fetch origin` and then `Pull origin`
+Or, in GitHub Desktop, click `Fetch origin` and then `Pull origin`.
 
 ## See Also
 

gulpfile.js

@@ -14,9 +14,14 @@ const gulp = require('gulp')
 const del = require('del')
 const browserSync = require('browser-sync')
 const JSON5 = require('json5')
-const gulpLoadPlugins = require('gulp-load-plugins')
 
-const $ = gulpLoadPlugins()
+const $ = require('gulp-load-plugins')({
+  postRequireTransforms: {
+    sass: (sass) => {
+      return sass(require('sass'))
+    }
+  }
+})
 
 gulp.task('assets', () =>
   gulp