Update dependency sshkit to v1.23.1

Gemfile.lock

@@ -2,6 +2,7 @@ GEM
   remote: https://rubygems.org/
   specs:
     addressable (2.4.0)
+    base64 (0.2.0)
     capybara (2.6.2)
       addressable
       mime-types (>= 1.16)
@@ -11,7 +12,6 @@ GEM
       xpath (~> 2.0)
     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)
@@ -20,9 +20,12 @@ GEM
     multi_json (1.11.2)
     net-scp (1.2.1)
       net-ssh (>= 2.6.5)
-    net-ssh (3.0.2)
+    net-sftp (2.1.2)
+      net-ssh (>= 2.6.5)
+    net-ssh (3.2.0)
     nokogiri (1.6.7.2)
       mini_portile2 (~> 2.0.0.rc2)
+    ostruct (0.6.0)
     rack (1.6.4)
     rack-test (0.6.3)
       rack (>= 1.0)
@@ -36,10 +39,12 @@ GEM
     site_prism (2.8)
       addressable (>= 2.3.3, < 3.0)
       capybara (>= 2.1, < 3.0)
-    sshkit (1.7.1)
-      colorize (>= 0.7.0)
+    sshkit (1.23.1)
+      base64
       net-scp (>= 1.1.2)
+      net-sftp (>= 2.1.2)
       net-ssh (>= 2.8.0)
+      ostruct
     thor (0.19.1)
     websocket (1.2.2)
     xpath (2.0.0)
@@ -55,3 +60,6 @@ DEPENDENCIES
   site_prism
   sshkit
   thor
+
+BUNDLED WITH
+   2.5.18