Bump jekyll from 4.2.0 to 4.2.1

Bumps [jekyll](https://github.com/jekyll/jekyll) from 4.2.0 to 4.2.1.
- [Release notes](https://github.com/jekyll/jekyll/releases)
- [Changelog](https://github.com/jekyll/jekyll/blob/master/History.markdown)
- [Commits](https://github.com/jekyll/jekyll/compare/v4.2.0...v4.2.1)

Gemfile

@@ -2,7 +2,7 @@
 source 'https://rubygems.org'
 
 # List of required gems
-gem 'jekyll', '~> 4.2.0'
+gem 'jekyll', '~> 4.2.1'
 gem 'jekyll-paginate', '~> 1.1.0'
 gem 'rouge', '~> 3.26.1'
 gem 'jekyll-redirect-from', '~> 0.16.0'

Gemfile.lock

 GEM
   remote: https://rubygems.org/
   specs:
-    addressable (2.7.0)
+    addressable (2.8.0)
       public_suffix (>= 2.0.2, < 5.0)
     colorator (1.1.0)
-    concurrent-ruby (1.1.7)
+    concurrent-ruby (1.1.9)
     em-websocket (0.5.2)
       eventmachine (>= 0.12.9)
       http_parser.rb (~> 0.6.0)
     ethon (0.14.0)
       ffi (>= 1.15.0)
     eventmachine (1.2.7)
-    ffi (1.15.3)
+    ffi (1.15.4)
     forwardable-extended (2.6.0)
     html-proofer (3.19.2)
       addressable (~> 2.3)
@@ -22,9 +22,9 @@ GEM
       typhoeus (~> 1.3)
       yell (~> 2.0)
     http_parser.rb (0.6.0)
-    i18n (1.8.5)
+    i18n (1.8.10)
       concurrent-ruby (~> 1.0)
-    jekyll (4.2.0)
+    jekyll (4.2.1)
       addressable (~> 2.4)
       colorator (~> 1.0)
       em-websocket (~> 0.5)
@@ -50,12 +50,12 @@ GEM
       jekyll (>= 3.7, < 5.0)
     jekyll-watch (2.2.1)
       listen (~> 3.0)
-    kramdown (2.3.0)
+    kramdown (2.3.1)
       rexml
     kramdown-parser-gfm (1.1.0)
       kramdown (~> 2.0)
     liquid (4.0.3)
-    listen (3.3.3)
+    listen (3.7.0)
       rb-fsevent (~> 0.10, >= 0.10.3)
       rb-inotify (~> 0.9, >= 0.9.10)
     mercenary (0.4.0)
@@ -71,10 +71,10 @@ GEM
     public_suffix (4.0.6)
     racc (1.5.2)
     rainbow (3.0.0)
-    rb-fsevent (0.10.4)
+    rb-fsevent (0.11.0)
     rb-inotify (0.10.1)
       ffi (~> 1.0)
-    rexml (3.2.4)
+    rexml (3.2.5)
     rouge (3.26.1)
     safe_yaml (1.0.5)
     sassc (2.4.0)
@@ -83,7 +83,7 @@ GEM
       unicode-display_width (~> 1.1, >= 1.1.1)
     typhoeus (1.4.0)
       ethon (>= 0.9.0)
-    unicode-display_width (1.7.0)
+    unicode-display_width (1.8.0)
     webrick (1.7.0)
     yaml-lint (0.0.10)
     yell (2.2.2)
@@ -93,7 +93,7 @@ PLATFORMS
 
 DEPENDENCIES
   html-proofer (~> 3.19.2)
-  jekyll (~> 4.2.0)
+  jekyll (~> 4.2.1)
   jekyll-feed (~> 0.15.1)
   jekyll-paginate (~> 1.1.0)
   jekyll-redirect-from (~> 0.16.0)