Update loofah to 2.2.3 (CVE-2018-16468)

Gemfile.lock

@@ -97,7 +97,7 @@ GEM
     connection_pool (2.2.1)
     crack (0.4.3)
       safe_yaml (~> 1.0.0)
-    crass (1.0.3)
+    crass (1.0.4)
     daemons (1.2.4)
     database_cleaner (1.5.3)
     diff-lcs (1.3)
@@ -199,7 +199,7 @@ GEM
       activesupport (>= 4)
       railties (>= 4)
       request_store (~> 1.0)
-    loofah (2.2.2)
+    loofah (2.2.3)
       crass (~> 1.0.2)
       nokogiri (>= 1.5.9)
     lumberjack (1.0.11)
@@ -490,4 +490,4 @@ DEPENDENCIES
   webmock (~> 1.24.2)
 
 BUNDLED WITH
-   1.17.0
+   1.17.1