Bump kramdown from 2.3.1 to 2.4.0

Bumps [kramdown](https://github.com/gettalong/kramdown) from 2.3.1 to 2.4.0.
- [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
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

Gemfile

@@ -10,7 +10,7 @@ gem 'nokogiri', '~> 1.13.4'
 gem 'rouge', '~> 2.2.1'
 gem 'therubyracer', '~>0.12.3'
 gem "jekyll-github-metadata", "~> 2.14"
-gem "kramdown", "~> 2.3.1"
+gem "kramdown", "~> 2.4.0"
 gem "kramdown-parser-gfm", "~> 1.1.0"
 
 group :dev do

Gemfile.lock

@@ -70,7 +70,7 @@ GEM
     jekyll-watch (2.2.1)
       listen (~> 3.0)
     json (2.5.1)
-    kramdown (2.3.1)
+    kramdown (2.4.0)
       rexml
     kramdown-parser-gfm (1.1.0)
       kramdown (~> 2.0)
@@ -131,7 +131,7 @@ DEPENDENCIES
   jekyll-github-metadata (~> 2.14)
   jekyll-paginate (~> 1.1.0)
   json (~> 2.3)
-  kramdown (~> 2.3.1)
+  kramdown (~> 2.4.0)
   kramdown-parser-gfm (~> 1.1.0)
   neat (~> 1.7.1)
   nokogiri (~> 1.13.4)