Update dependency jekyll to v4.3.4

docs/Gemfile.lock

@@ -1,10 +1,10 @@
 GEM
   remote: https://rubygems.org/
   specs:
-    addressable (2.8.6)
-      public_suffix (>= 2.0.2, < 6.0)
+    addressable (2.8.7)
+      public_suffix (>= 2.0.2, < 7.0)
     colorator (1.1.0)
-    concurrent-ruby (1.2.2)
+    concurrent-ruby (1.2.3)
     em-websocket (0.5.3)
       eventmachine (>= 0.12.9)
       http_parser.rb (~> 0)
@@ -35,9 +35,9 @@ GEM
     ffi (1.16.3)
     forwardable-extended (2.6.0)
     http_parser.rb (0.8.0)
-    i18n (1.14.1)
+    i18n (1.14.6)
       concurrent-ruby (~> 1.0)
-    jekyll (4.3.3)
+    jekyll (4.3.4)
       addressable (~> 2.4)
       colorator (~> 1.0)
       em-websocket (~> 0.5)
@@ -81,7 +81,8 @@ GEM
     rb-fsevent (0.11.2)
     rb-inotify (0.10.1)
       ffi (~> 1.0)
-    rexml (3.2.6)
+    rexml (3.2.9)
+      strscan
     rouge (3.30.0)
     ruby2_keywords (0.0.5)
     safe_yaml (1.0.5)
@@ -90,6 +91,7 @@ GEM
     sawyer (0.9.2)
       addressable (>= 2.3.5)
       faraday (>= 0.17.3, < 3)
+    strscan (3.1.0)
     terminal-table (1.8.0)
       unicode-display_width (~> 1.1, >= 1.1.1)
     unicode-display_width (1.8.0)