Upgrade to Jekyll 4

Gemfile

@@ -9,7 +9,7 @@ ruby RUBY_VERSION
 #
 # This will help ensure the proper Jekyll version is running.
 # Happy Jekylling!
-gem "jekyll", "3.6.3"
+gem "jekyll", "4.1.0"
 
 # This is the default theme for new Jekyll sites. You may change this to anything you like.
 gem "minima"

Gemfile.lock

@@ -4,49 +4,72 @@ GEM
     addressable (2.7.0)
       public_suffix (>= 2.0.2, < 5.0)
     colorator (1.1.0)
+    concurrent-ruby (1.1.6)
+    em-websocket (0.5.1)
+      eventmachine (>= 0.12.9)
+      http_parser.rb (~> 0.6.0)
+    eventmachine (1.2.7)
     ffi (1.13.1)
     forwardable-extended (2.6.0)
-    jekyll (3.6.3)
+    http_parser.rb (0.6.0)
+    i18n (1.8.3)
+      concurrent-ruby (~> 1.0)
+    jekyll (4.1.0)
       addressable (~> 2.4)
       colorator (~> 1.0)
-      jekyll-sass-converter (~> 1.0)
+      em-websocket (~> 0.5)
-      jekyll-watch (~> 1.1)
+      i18n (~> 1.0)
-      kramdown (~> 1.14)
+      jekyll-sass-converter (~> 2.0)
+      jekyll-watch (~> 2.0)
+      kramdown (~> 2.1)
+      kramdown-parser-gfm (~> 1.0)
       liquid (~> 4.0)
-      mercenary (~> 0.3.3)
+      mercenary (~> 0.4.0)
       pathutil (~> 0.9)
-      rouge (>= 1.7, < 3)
+      rouge (~> 3.0)
       safe_yaml (~> 1.0)
-    jekyll-sass-converter (1.5.2)
+      terminal-table (~> 1.8)
-      sass (~> 3.4)
+    jekyll-feed (0.13.0)
-    jekyll-watch (1.5.1)
+      jekyll (>= 3.7, < 5.0)
+    jekyll-sass-converter (2.1.0)
+      sassc (> 2.0.1, < 3.0)
+    jekyll-seo-tag (2.6.1)
+      jekyll (>= 3.3, < 5.0)
+    jekyll-watch (2.2.1)
       listen (~> 3.0)
-    kramdown (1.17.0)
+    kramdown (2.2.1)
+      rexml
+    kramdown-parser-gfm (1.1.0)
+      kramdown (~> 2.0)
     liquid (4.0.3)
     listen (3.2.1)
       rb-fsevent (~> 0.10, >= 0.10.3)
       rb-inotify (~> 0.9, >= 0.9.10)
-    mercenary (0.3.6)
+    mercenary (0.4.0)
-    minima (1.2.0)
+    minima (2.5.1)
+      jekyll (>= 3.5, < 5.0)
+      jekyll-feed (~> 0.9)
+      jekyll-seo-tag (~> 2.1)
     pathutil (0.16.2)
       forwardable-extended (~> 2.6)
     public_suffix (4.0.5)
     rb-fsevent (0.10.4)
     rb-inotify (0.10.1)
       ffi (~> 1.0)
-    rouge (1.11.1)
+    rexml (3.2.4)
+    rouge (3.20.0)
     safe_yaml (1.0.5)
-    sass (3.7.4)
+    sassc (2.4.0)
-      sass-listen (~> 4.0.0)
+      ffi (~> 1.9)
-    sass-listen (4.0.0)
+    terminal-table (1.8.0)
-      rb-fsevent (~> 0.9, >= 0.9.4)
+      unicode-display_width (~> 1.1, >= 1.1.1)
-      rb-inotify (~> 0.9, >= 0.9.7)
+    unicode-display_width (1.7.0)
 
 PLATFORMS
   ruby
 
 DEPENDENCIES
-  jekyll (= 3.6.3)
+  jekyll (= 4.1.0)
   minima
   rouge