Update gem dependencies

Gemfile.lock

@@ -28,7 +28,7 @@ GEM
     ffi (1.9.25)
     fspath (3.1.0)
     highline (1.7.10)
-    html-pipeline (2.8.3)
+    html-pipeline (2.8.4)
       activesupport (>= 2)
       nokogiri (>= 1.4)
     i18n (1.0.1)
@@ -63,14 +63,14 @@ GEM
     rack (2.0.5)
     rack-protection (2.0.3)
       rack
-    rack-test (1.0.0)
+    rack-test (1.1.0)
       rack (>= 1.0, < 3)
     rake (12.3.1)
     rb-fsevent (0.10.3)
     rb-inotify (0.9.10)
       ffi (>= 0.5.0, < 2)
     rr (1.2.1)
-    sass (3.5.6)
+    sass (3.5.7)
       sass-listen (~> 4.0.0)
     sass-listen (4.0.0)
       rb-fsevent (~> 0.9, >= 0.9.4)
@@ -107,18 +107,18 @@ GEM
       strings (~> 0.1.0)
       tty-screen (~> 0.6.4)
       tty-which (~> 0.3.0)
-    tty-screen (0.6.4)
+    tty-screen (0.6.5)
     tty-which (0.3.0)
     typhoeus (1.3.0)
       ethon (>= 0.9.0)
     tzinfo (1.2.5)
       thread_safe (~> 0.1)
-    uglifier (4.1.14)
+    uglifier (4.1.17)
       execjs (>= 0.3.0, < 3)
     unicode-display_width (1.3.3)
     unicode_utils (1.4.0)
     unix_utils (0.0.15)
-    yajl-ruby (1.4.0)
+    yajl-ruby (1.4.1)
 
 PLATFORMS
   ruby