chore(deps): bump nokogiri from 1.12.5 to 1.13.3 in /docs

Bumps [nokogiri](https://github.com/sparklemotion/nokogiri) from 1.12.5 to 1.13.3.
- [Release notes](https://github.com/sparklemotion/nokogiri/releases)
- [Changelog](https://github.com/sparklemotion/nokogiri/blob/main/CHANGELOG.md)
- [Commits](sparklemotion/nokogiri@v1.12.5...v1.13.3)

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

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

docs/Gemfile.lock

@@ -225,15 +225,17 @@ GEM
       jekyll-seo-tag (~> 2.1)
     minitest (5.14.4)
     multipart-post (2.1.1)
-    nokogiri (1.12.5-x86_64-darwin)
+    nokogiri (1.13.3-x86_64-darwin)
+      racc (~> 1.4)
+    nokogiri (1.13.3-x86_64-linux)
       racc (~> 1.4)
     octokit (4.21.0)
       faraday (>= 0.9)
       sawyer (~> 0.8.0, >= 0.5.3)
     pathutil (0.16.2)
       forwardable-extended (~> 2.6)
     public_suffix (4.0.6)
-    racc (1.5.2)
+    racc (1.6.0)
     rb-fsevent (0.11.0)
     rb-inotify (0.10.1)
       ffi (~> 1.0)
@@ -270,6 +272,7 @@ GEM
 
 PLATFORMS
   x86_64-darwin-18
+  x86_64-linux
 
 DEPENDENCIES
   github-pages