Update dependency capybara to v3

Gemfile.lock

@@ -1,31 +1,33 @@
 GEM
   remote: https://rubygems.org/
   specs:
-    addressable (2.4.0)
-    capybara (2.6.2)
+    addressable (2.8.6)
+      public_suffix (>= 2.0.2, < 6.0)
+    capybara (2.18.0)
       addressable
-      mime-types (>= 1.16)
+      mini_mime (>= 0.1.3)
       nokogiri (>= 1.3.3)
       rack (>= 1.0.0)
       rack-test (>= 0.5.4)
-      xpath (~> 2.0)
+      xpath (>= 2.0, < 4.0)
     childprocess (0.5.9)
       ffi (~> 1.0, >= 1.0.11)
     colorize (0.7.7)
     ffi (1.9.10)
-    mime-types (3.0)
-      mime-types-data (~> 3.2015)
-    mime-types-data (3.2016.0221)
-    mini_portile2 (2.0.0)
+    mini_mime (1.1.5)
+    mini_portile2 (2.8.5)
     multi_json (1.11.2)
     net-scp (1.2.1)
       net-ssh (>= 2.6.5)
     net-ssh (3.0.2)
-    nokogiri (1.6.7.2)
-      mini_portile2 (~> 2.0.0.rc2)
-    rack (1.6.4)
-    rack-test (0.6.3)
-      rack (>= 1.0)
+    nokogiri (1.16.3)
+      mini_portile2 (~> 2.8.2)
+      racc (~> 1.4)
+    public_suffix (5.0.4)
+    racc (1.7.3)
+    rack (3.0.10)
+    rack-test (2.1.0)
+      rack (>= 1.3)
     rake (10.5.0)
     rubyzip (1.2.0)
     selenium-webdriver (2.52.0)
@@ -42,8 +44,8 @@ GEM
       net-ssh (>= 2.8.0)
     thor (0.19.1)
     websocket (1.2.2)
-    xpath (2.0.0)
-      nokogiri (~> 1.3)
+    xpath (3.2.0)
+      nokogiri (~> 1.8)
 
 PLATFORMS
   ruby
@@ -55,3 +57,6 @@ DEPENDENCIES
   site_prism
   sshkit
   thor
+
+BUNDLED WITH
+   2.5.7