Bump kramdown from 2.3.0 to 2.3.1

Bumps [kramdown](https://github.com/gettalong/kramdown) from 2.3.0 to 2.3.1.
- [Release notes](https://github.com/gettalong/kramdown/releases)
- [Changelog](https://github.com/gettalong/kramdown/blob/master/doc/news.page)
- [Commits](https://github.com/gettalong/kramdown/commits)

---
updated-dependencies:
- dependency-name: kramdown
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

Gemfile.lock

@@ -1,7 +1,7 @@
 GEM
   remote: https://rubygems.org/
   specs:
-    activesupport (5.2.4.4)
+    activesupport (5.2.8.1)
       concurrent-ruby (~> 1.0, >= 1.0.2)
       i18n (>= 0.7, < 2)
       minitest (~> 5.1)
@@ -45,8 +45,8 @@ GEM
       multi_json (~> 1.0)
       net-http-persistent (~> 2.9)
       net-http-pipeline
-    github-pages (209)
-      github-pages-health-check (= 1.16.1)
+    github-pages (217)
+      github-pages-health-check (= 1.17.2)
       jekyll (= 3.9.0)
       jekyll-avatar (= 0.7.0)
       jekyll-coffeescript (= 1.1.1)
@@ -61,39 +61,25 @@ GEM
       jekyll-readme-index (= 0.3.0)
       jekyll-redirect-from (= 0.16.0)
       jekyll-relative-links (= 0.6.1)
-      jekyll-remote-theme (= 0.4.2)
+      jekyll-remote-theme (= 0.4.3)
       jekyll-sass-converter (= 1.5.2)
-      jekyll-seo-tag (= 2.6.1)
+      jekyll-seo-tag (= 2.7.1)
       jekyll-sitemap (= 1.4.0)
-      jekyll-swiss (= 1.0.0)
-      jekyll-theme-architect (= 0.1.1)
-      jekyll-theme-cayman (= 0.1.1)
-      jekyll-theme-dinky (= 0.1.1)
-      jekyll-theme-hacker (= 0.1.2)
-      jekyll-theme-leap-day (= 0.1.1)
-      jekyll-theme-merlot (= 0.1.1)
-      jekyll-theme-midnight (= 0.1.1)
-      jekyll-theme-minimal (= 0.1.1)
-      jekyll-theme-modernist (= 0.1.1)
-      jekyll-theme-primer (= 0.5.4)
-      jekyll-theme-slate (= 0.1.1)
-      jekyll-theme-tactile (= 0.1.1)
-      jekyll-theme-time-machine (= 0.1.1)
       jekyll-titles-from-headings (= 0.5.3)
       jemoji (= 0.12.0)
-      kramdown (= 2.3.0)
+      kramdown (= 2.3.1)
       kramdown-parser-gfm (= 1.1.0)
       liquid (= 4.0.3)
       mercenary (~> 0.3)
       minima (= 2.5.1)
       nokogiri (>= 1.10.4, < 2.0)
-      rouge (= 3.23.0)
+      rouge (= 3.26.0)
       terminal-table (~> 1.4)
-    github-pages-health-check (1.16.1)
+    github-pages-health-check (1.17.2)
       addressable (~> 2.3)
       dnsruby (~> 1.60)
       octokit (~> 4.0)
-      public_suffix (~> 3.0)
+      public_suffix (>= 2.0.2, < 5.0)
       typhoeus (~> 1.3)
     highline (2.0.3)
     html-pipeline (2.14.0)
@@ -148,58 +134,17 @@ GEM
       jekyll (>= 3.3, < 5.0)
     jekyll-relative-links (0.6.1)
       jekyll (>= 3.3, < 5.0)
-    jekyll-remote-theme (0.4.2)
+    jekyll-remote-theme (0.4.3)
       addressable (~> 2.0)
       jekyll (>= 3.5, < 5.0)
       jekyll-sass-converter (>= 1.0, <= 3.0.0, != 2.0.0)
       rubyzip (>= 1.3.0, < 3.0)
     jekyll-sass-converter (1.5.2)
       sass (~> 3.4)
-    jekyll-seo-tag (2.6.1)
-      jekyll (>= 3.3, < 5.0)
+    jekyll-seo-tag (2.7.1)
+      jekyll (>= 3.8, < 5.0)
     jekyll-sitemap (1.4.0)
       jekyll (>= 3.7, < 5.0)
-    jekyll-swiss (1.0.0)
-    jekyll-theme-architect (0.1.1)
-      jekyll (~> 3.5)
-      jekyll-seo-tag (~> 2.0)
-    jekyll-theme-cayman (0.1.1)
-      jekyll (~> 3.5)
-      jekyll-seo-tag (~> 2.0)
-    jekyll-theme-dinky (0.1.1)
-      jekyll (~> 3.5)
-      jekyll-seo-tag (~> 2.0)
-    jekyll-theme-hacker (0.1.2)
-      jekyll (> 3.5, < 5.0)
-      jekyll-seo-tag (~> 2.0)
-    jekyll-theme-leap-day (0.1.1)
-      jekyll (~> 3.5)
-      jekyll-seo-tag (~> 2.0)
-    jekyll-theme-merlot (0.1.1)
-      jekyll (~> 3.5)
-      jekyll-seo-tag (~> 2.0)
-    jekyll-theme-midnight (0.1.1)
-      jekyll (~> 3.5)
-      jekyll-seo-tag (~> 2.0)
-    jekyll-theme-minimal (0.1.1)
-      jekyll (~> 3.5)
-      jekyll-seo-tag (~> 2.0)
-    jekyll-theme-modernist (0.1.1)
-      jekyll (~> 3.5)
-      jekyll-seo-tag (~> 2.0)
-    jekyll-theme-primer (0.5.4)
-      jekyll (> 3.5, < 5.0)
-      jekyll-github-metadata (~> 2.9)
-      jekyll-seo-tag (~> 2.0)
-    jekyll-theme-slate (0.1.1)
-      jekyll (~> 3.5)
-      jekyll-seo-tag (~> 2.0)
-    jekyll-theme-tactile (0.1.1)
-      jekyll (~> 3.5)
-      jekyll-seo-tag (~> 2.0)
-    jekyll-theme-time-machine (0.1.1)
-      jekyll (~> 3.5)
-      jekyll-seo-tag (~> 2.0)
     jekyll-titles-from-headings (0.5.3)
       jekyll (>= 3.3, < 5.0)
     jekyll-watch (2.2.1)
@@ -210,7 +155,7 @@ GEM
       jekyll (>= 3.0, < 5.0)
     json (2.5.1)
     json_pure (2.5.1)
-    kramdown (2.3.0)
+    kramdown (2.3.1)
       rexml
     kramdown-parser-gfm (1.1.0)
       kramdown (~> 2.0)
@@ -234,6 +179,8 @@ GEM
     nokogiri (1.13.9)
       mini_portile2 (~> 2.8.0)
       racc (~> 1.4)
+    nokogumbo (2.0.5)
+      nokogiri (~> 1.8, >= 1.8.4)
     octokit (4.20.0)
       faraday (>= 0.9)
       sawyer (~> 0.8.0, >= 0.5.3)
@@ -250,7 +197,7 @@ GEM
     rb-inotify (0.10.1)
       ffi (~> 1.0)
     rexml (3.2.5)
-    rouge (3.23.0)
+    rouge (3.26.0)
     rspec (3.10.0)
       rspec-core (~> 3.10.0)
       rspec-expectations (~> 3.10.0)
@@ -287,7 +234,7 @@ GEM
     thread_safe (0.3.6)
     tidy_ffi (1.0.1)
       ffi (~> 1.2)
-    travis (1.10.0)
+    travis (1.11.1)
       faraday (~> 1.0)
       faraday_middleware (~> 1.0)
       gh (~> 0.13)
@@ -303,15 +250,16 @@ GEM
       unf_ext
     unf_ext (0.0.7.7)
     unicode-display_width (1.7.0)
-    validate-website (1.11.0)
+    validate-website (1.11.1)
       crass (~> 1)
+      nokogumbo (~> 2.0)
       paint (~> 2)
       slop (~> 4.6)
       spidr (~> 0.6)
       tidy_ffi (~> 1.0)
       w3c_validators (~> 1.3)
       webrick (~> 1)
-    w3c_validators (1.3.6)
+    w3c_validators (1.3.7)
       json (>= 1.8)
       nokogiri (~> 1.6)
       rexml (~> 3.2)