Bump nokogiri from 1.13.0 to 1.13.6

Bumps [nokogiri](https://github.com/sparklemotion/nokogiri) from 1.13.0 to 1.13.6.
- [Release notes](https://github.com/sparklemotion/nokogiri/releases)
- [Changelog](https://github.com/sparklemotion/nokogiri/blob/main/CHANGELOG.md)
- [Commits](sparklemotion/nokogiri@v1.13.0...v1.13.6)

---
updated-dependencies:
- dependency-name: nokogiri
  dependency-type: indirect
...

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

Author: dependabot[bot]

Gemfile.lock

@@ -67,7 +67,9 @@ GEM
       jekyll-feed (~> 0.9)
       jekyll-seo-tag (~> 2.1)
     minitest (5.15.0)
-    nokogiri (1.13.0-x86_64-darwin)
+    nokogiri (1.13.6-x86_64-darwin)
+      racc (~> 1.4)
+    nokogiri (1.13.6-x86_64-linux)
       racc (~> 1.4)
     pathutil (0.16.2)
       forwardable-extended (~> 2.6)
@@ -95,6 +97,7 @@ GEM
 
 PLATFORMS
   x86_64-darwin-19
+  x86_64-linux
 
 DEPENDENCIES
   jekyll (~> 4.0.0)