jekyll: Update the dependencies (security, CVE-2021-28834)

This fixes a potential security issue (reported by bundler-audit) by
updating kramdown to 2.3.1 for CVE-2021-28834 [0].

[0]: https://github.com/advisories/GHSA-52p9-v744-mwjj

pkgs/applications/misc/jekyll/basic/Gemfile.lock

@@ -1,7 +1,7 @@
 GEM
   remote: https://rubygems.org/
   specs:
-    activesupport (6.1.3)
+    activesupport (6.1.3.1)
       concurrent-ruby (~> 1.0, >= 1.0.2)
       i18n (>= 1.6, < 2)
       minitest (>= 5.1)
@@ -15,14 +15,14 @@ GEM
       eventmachine (>= 0.12.9)
       http_parser.rb (~> 0.6.0)
     eventmachine (1.2.7)
-    ffi (1.14.2)
+    ffi (1.15.0)
     forwardable-extended (2.6.0)
     gemoji (3.0.1)
     html-pipeline (2.14.0)
       activesupport (>= 2)
       nokogiri (>= 1.4)
     http_parser.rb (0.6.0)
-    i18n (1.8.9)
+    i18n (1.8.10)
       concurrent-ruby (~> 1.0)
     jekyll (4.2.0)
       addressable (~> 2.4)
@@ -56,18 +56,18 @@ GEM
       gemoji (~> 3.0)
       html-pipeline (~> 2.2)
       jekyll (>= 3.0, < 5.0)
-    kramdown (2.3.0)
+    kramdown (2.3.1)
       rexml
     kramdown-parser-gfm (1.1.0)
       kramdown (~> 2.0)
     liquid (4.0.3)
-    listen (3.4.1)
+    listen (3.5.1)
       rb-fsevent (~> 0.10, >= 0.10.3)
       rb-inotify (~> 0.9, >= 0.9.10)
     mercenary (0.4.0)
     mini_portile2 (2.5.0)
     minitest (5.14.4)
-    nokogiri (1.11.1)
+    nokogiri (1.11.2)
       mini_portile2 (~> 2.5.0)
       racc (~> 1.4)
     pathutil (0.16.2)