Bump asset_sync

Gemfile

@@ -235,7 +235,7 @@ group :production do # we don"t install these on travis to speed up test runs
 
   # Third party asset hosting
 
-  gem "asset_sync", "2.2.0", require: false
+  gem "asset_sync", "2.4.0", require: false
 end
 
 group :development do

Gemfile.lock

@@ -54,7 +54,7 @@ GEM
       public_suffix (>= 2.0.2, < 4.0)
     aes_key_wrap (1.0.1)
     arel (8.0.0)
-    asset_sync (2.2.0)
+    asset_sync (2.4.0)
       activemodel (>= 4.1.0)
       fog-core
       mime-types (>= 2.99)
@@ -769,7 +769,7 @@ DEPENDENCIES
   acts-as-taggable-on (= 5.0.0)
   acts_as_api (= 1.0.1)
   addressable (= 2.5.2)
-  asset_sync (= 2.2.0)
+  asset_sync (= 2.4.0)
   autoprefixer-rails (= 8.2.0)
   bootstrap-sass (= 3.3.7)
   bootstrap-switch-rails (= 3.3.3)