Update to an even newer jekyll, so we can update to a newer kramdown

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", "3.9.4"
 
 # This is the default theme for new Jekyll sites. You may change this to anything you like.
 gem "minima", "~> 2.0"

Gemfile.lock

@@ -4,29 +4,41 @@ GEM
     addressable (2.8.6)
       public_suffix (>= 2.0.2, < 6.0)
     colorator (1.1.0)
+    concurrent-ruby (1.2.3)
+    em-websocket (0.5.3)
+      eventmachine (>= 0.12.9)
+      http_parser.rb (~> 0)
+    eventmachine (1.2.7)
+    eventmachine (1.2.7-x86-mingw32)
     ffi (1.16.3)
     ffi (1.16.3-x86-mingw32)
     forwardable-extended (2.6.0)
-    jekyll (3.6.3)
+    http_parser.rb (0.8.0)
+    i18n (1.14.1)
+      concurrent-ruby (~> 1.0)
+    jekyll (3.9.4)
       addressable (~> 2.4)
       colorator (~> 1.0)
+      em-websocket (~> 0.5)
+      i18n (>= 0.7, < 2)
       jekyll-sass-converter (~> 1.0)
-      jekyll-watch (~> 1.1)
-      kramdown (~> 1.14)
+      jekyll-watch (~> 2.0)
+      kramdown (>= 1.17, < 3)
       liquid (~> 4.0)
       mercenary (~> 0.3.3)
       pathutil (~> 0.9)
-      rouge (>= 1.7, < 3)
+      rouge (>= 1.7, < 4)
       safe_yaml (~> 1.0)
-    jekyll-feed (0.11.0)
-      jekyll (~> 3.3)
+    jekyll-feed (0.17.0)
+      jekyll (>= 3.7, < 5.0)
     jekyll-sass-converter (1.5.2)
       sass (~> 3.4)
-    jekyll-seo-tag (2.6.1)
-      jekyll (>= 3.3, < 5.0)
-    jekyll-watch (1.5.1)
+    jekyll-seo-tag (2.8.0)
+      jekyll (>= 3.8, < 5.0)
+    jekyll-watch (2.2.1)
       listen (~> 3.0)
-    kramdown (1.17.0)
+    kramdown (2.4.0)
+      rexml
     liquid (4.0.4)
     listen (3.8.0)
       rb-fsevent (~> 0.10, >= 0.10.3)
@@ -42,7 +54,8 @@ GEM
     rb-fsevent (0.11.2)
     rb-inotify (0.10.1)
       ffi (~> 1.0)
-    rouge (2.2.1)
+    rexml (3.2.6)
+    rouge (3.30.0)
     safe_yaml (1.0.5)
     sass (3.7.4)
       sass-listen (~> 4.0.0)
@@ -55,7 +68,7 @@ PLATFORMS
   x86-mingw32
 
 DEPENDENCIES
-  jekyll (= 3.6.3)
+  jekyll (= 3.9.4)
   jekyll-feed (~> 0.6)
   minima (~> 2.0)