Bump development dependencies

Gemfile.lock

@@ -6,18 +6,18 @@ PATH
 GEM
   remote: https://rubygems.org/
   specs:
-    addressable (2.5.1)
-      public_suffix (~> 2.0, >= 2.0.2)
+    addressable (2.5.2)
+      public_suffix (>= 2.0.2, < 4.0)
     ast (2.3.0)
     chandler (0.7.0)
       netrc
       octokit (>= 2.2.0)
     coderay (1.1.2)
     docile (1.1.5)
-    faraday (0.12.1)
+    faraday (0.13.1)
       multipart-post (>= 1.2, < 3)
     json (2.1.0)
-    kramdown (1.13.2)
+    kramdown (1.16.2)
     mdl (0.4.0)
       kramdown (~> 1.12, >= 1.12.0)
       mixlib-cli (~> 1.7, >= 1.7.0)
@@ -28,7 +28,7 @@ GEM
     mixlib-config (2.2.4)
     multipart-post (2.0.0)
     netrc (0.11.0)
-    octokit (4.7.0)
+    octokit (4.8.0)
       sawyer (~> 0.8.0, >= 0.5.3)
     parallel (1.12.1)
     parser (2.4.0.2)
@@ -37,7 +37,7 @@ GEM
     pry (0.11.3)
       coderay (~> 1.1.0)
       method_source (~> 0.9.0)
-    public_suffix (2.0.5)
+    public_suffix (3.0.1)
     rainbow (3.0.0)
     rake (12.3.0)
     rake-compiler (1.0.4)