[Security] Bump kramdown from 1.17.0 to 2.3.0

Bumps [kramdown](https://github.com/gettalong/kramdown) from 1.17.0 to 2.3.0. **This update includes a security fix.**
- [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)

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

Gemfile.lock

@@ -44,21 +44,21 @@ GEM
     extras (0.3.0)
       forwardable-extended (~> 2.5)
     fastimage (2.1.7)
-    ffi (1.12.2)
+    ffi (1.13.1)
     font-awesome-sass (5.13.0)
       sassc (>= 1.11)
     forwardable-extended (2.6.0)
     http_parser.rb (0.6.0)
     i18n (0.9.5)
       concurrent-ruby (~> 1.0)
-    jekyll (3.8.6)
+    jekyll (3.9.0)
       addressable (~> 2.4)
       colorator (~> 1.0)
       em-websocket (~> 0.5)
       i18n (~> 0.7)
       jekyll-sass-converter (~> 1.0)
       jekyll-watch (~> 2.0)
-      kramdown (~> 1.14)
+      kramdown (>= 1.17, < 3)
       liquid (~> 4.0)
       mercenary (~> 0.3.3)
       pathutil (~> 0.9)
@@ -86,7 +86,8 @@ GEM
       jekyll (>= 3.7, < 5.0)
     jekyll-watch (2.2.1)
       listen (~> 3.0)
-    kramdown (1.17.0)
+    kramdown (2.3.0)
+      rexml
     liquid (4.0.3)
     liquid-tag-parser (1.9.0)
       extras (~> 0.3)
@@ -106,7 +107,7 @@ GEM
     pathutil (0.16.2)
       forwardable-extended (~> 2.6)
     popper_js (1.16.0)
-    public_suffix (4.0.3)
+    public_suffix (4.0.5)
     rack (2.2.3)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
@@ -122,10 +123,11 @@ GEM
       rake (>= 0.8.7)
       thor (>= 0.19.0, < 2.0)
     rake (13.0.1)
-    rb-fsevent (0.10.3)
+    rb-fsevent (0.10.4)
     rb-inotify (0.10.1)
       ffi (~> 1.0)
-    rouge (3.16.0)
+    rexml (3.2.4)
+    rouge (3.21.0)
     safe_yaml (1.0.5)
     sass (3.7.4)
       sass-listen (~> 4.0.0)