Bump bourbon from 4.3.4 to 6.0.0

Bumps [bourbon](https://github.com/thoughtbot/bourbon) from 4.3.4 to 6.0.0.
- [Release notes](https://github.com/thoughtbot/bourbon/releases)
- [Changelog](https://github.com/thoughtbot/bourbon/blob/master/CHANGELOG.md)
- [Commits](thoughtbot/bourbon@v4.3.4...v6.0.0)

Signed-off-by: dependabot-preview[bot] <[email protected]>

Gemfile

@@ -29,7 +29,7 @@ gem 'font-awesome-sass'
 
 # Neat bourbon RWD Framework
 gem 'neat', '~> 1.8'
-gem 'bourbon', '~> 4.2'
+gem 'bourbon', '~> 6.0'
 gem 'bitters'
 
 # Use jquery as the JavaScript library

Gemfile.lock

@@ -119,8 +119,7 @@ GEM
       bourbon (>= 4.2)
       sass (>= 3.4)
       thor
-    bourbon (4.3.4)
-      sass (~> 3.4)
+    bourbon (6.0.0)
       thor (~> 0.19)
     builder (3.2.3)
     byebug (10.0.1)
@@ -157,7 +156,7 @@ GEM
     execjs (2.7.0)
     faraday (0.17.1)
       multipart-post (>= 1.2, < 3)
-    ffi (1.9.25)
+    ffi (1.11.3)
     figaro (1.1.1)
       thor (~> 0.14)
     filters_spam (0.5)
@@ -314,8 +313,8 @@ GEM
     raindrops (0.19.0)
     rake (13.0.1)
     rb-fsevent (0.10.3)
-    rb-inotify (0.9.10)
-      ffi (>= 0.5.0, < 2)
+    rb-inotify (0.10.0)
+      ffi (~> 1.0)
     rdoc (4.3.0)
     readingtime (0.4.0)
     redis (4.0.1)
@@ -397,7 +396,7 @@ GEM
       actionpack (>= 4.2, < 6)
       activesupport (>= 4.2, < 6)
     ruby_dep (1.5.0)
-    sass (3.5.5)
+    sass (3.7.4)
       sass-listen (~> 4.0.0)
     sass-listen (4.0.0)
       rb-fsevent (~> 0.9, >= 0.9.4)
@@ -465,7 +464,7 @@ DEPENDENCIES
   actionpack-page_caching
   active_link_to
   bitters
-  bourbon (~> 4.2)
+  bourbon (~> 6.0)
   byebug
   coderay
   coffee-rails (~> 4.1.0)