Bump autoprefixer-rails

Gemfile

@@ -57,7 +57,7 @@ gem "rack-cors", "0.4.0", require: "rack/cors"
 gem "bootstrap-sass", "3.3.6"
 gem "compass-rails",  "2.0.5"
 gem "sass-rails",     "5.0.4"
-gem "autoprefixer-rails", "6.3.6.2"
+gem "autoprefixer-rails", "6.4.0.2"
 gem "bootstrap-switch-rails", "3.3.3"
 
 # Database

Gemfile.lock

@@ -56,7 +56,7 @@ GEM
       unf
     ast (2.3.0)
     attr_required (1.0.1)
-    autoprefixer-rails (6.3.6.2)
+    autoprefixer-rails (6.4.0.2)
       execjs
     backbone-on-rails (1.2.0.0)
       eco
@@ -918,7 +918,7 @@ DEPENDENCIES
   acts_as_api (= 0.4.3)
   addressable (= 2.3.8)
   asset_sync (= 1.1.0)
-  autoprefixer-rails (= 6.3.6.2)
+  autoprefixer-rails (= 6.4.0.2)
   backbone-on-rails (= 1.2.0.0)
   bootstrap-sass (= 3.3.6)
   bootstrap-switch-rails (= 3.3.3)