Bump sprockets from 2.2.2 to 2.2.3

Bumps [sprockets](https://github.com/rails/sprockets) from 2.2.2 to 2.2.3.
- [Release notes](https://github.com/rails/sprockets/releases)
- [Changelog](https://github.com/rails/sprockets/blob/master/CHANGELOG.md)
- [Commits](rails/sprockets@v2.2.2...v2.2.3)

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

Gemfile.lock

@@ -87,7 +87,7 @@ GEM
       activesupport (>= 3.1, < 4.1)
       haml (>= 3.1, < 4.1)
       railties (>= 3.1, < 4.1)
-    hike (1.2.1)
+    hike (1.2.3)
     i18n (0.6.1)
     journey (1.0.4)
     jquery-rails (2.2.1)
@@ -99,13 +99,13 @@ GEM
       mime-types (~> 1.16)
       treetop (~> 1.4.8)
     mime-types (1.22)
-    multi_json (1.7.2)
+    multi_json (1.14.1)
     nokogiri (1.5.9)
     nokogiri (1.5.9-x86-mingw32)
     pg (0.15.0)
     pg (0.15.0-x86-mingw32)
     polyglot (0.3.3)
-    rack (1.4.5)
+    rack (1.4.7)
     rack-cache (1.2)
       rack (>= 0.4)
     rack-ssl (1.3.3)
@@ -152,15 +152,15 @@ GEM
       multi_json (~> 1.0)
       rubyzip
       websocket (~> 1.0.4)
-    sprockets (2.2.2)
+    sprockets (2.2.3)
       hike (~> 1.2)
       multi_json (~> 1.0)
       rack (~> 1.0)
       tilt (~> 1.1, != 1.3.0)
     sqlite3 (1.3.7)
     sqlite3 (1.3.7-x86-mingw32)
     thor (0.18.1)
-    tilt (1.3.6)
+    tilt (1.4.1)
     treetop (1.4.12)
       polyglot
       polyglot (>= 0.3.1)