Bump nokogiri from 1.12.5 to 1.13.6 in /docs

Bumps [nokogiri](https://github.com/sparklemotion/nokogiri) from 1.12.5 to 1.13.6.
- [Release notes](https://github.com/sparklemotion/nokogiri/releases)
- [Changelog](https://github.com/sparklemotion/nokogiri/blob/main/CHANGELOG.md)
- [Commits](https://github.com/sparklemotion/nokogiri/compare/v1.12.5...v1.13.6)

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

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

docs/Gemfile.lock

@@ -24,6 +24,7 @@ GEM
       http_parser.rb (~> 0)
     ethon (0.15.0)
       ffi (>= 1.15.0)
+    eventmachine (1.2.7)
     eventmachine (1.2.7-x64-mingw32)
     execjs (2.8.1)
     faraday (1.10.0)
@@ -49,6 +50,7 @@ GEM
     faraday-patron (1.0.0)
     faraday-rack (1.0.0)
     faraday-retry (1.0.3)
+    ffi (1.15.5)
     ffi (1.15.5-x64-mingw32)
     forwardable-extended (2.6.0)
     gemoji (3.0.1)
@@ -224,7 +226,9 @@ GEM
       jekyll-seo-tag (~> 2.1)
     minitest (5.15.0)
     multipart-post (2.2.0)
-    nokogiri (1.12.5-x64-mingw32)
+    nokogiri (1.13.6-x64-mingw32)
+      racc (~> 1.4)
+    nokogiri (1.13.6-x86_64-linux)
       racc (~> 1.4)
     octokit (4.24.0)
       faraday (>= 1, < 3)
@@ -264,12 +268,14 @@ GEM
     unf (0.1.4)
       unf_ext
     unf_ext (0.0.8.2)
+    unf_ext (0.0.8.2-x64-mingw32)
     unicode-display_width (1.8.0)
     wdm (0.1.1)
     zeitwerk (2.5.4)
 
 PLATFORMS
   x64-mingw32
+  x86_64-linux
 
 DEPENDENCIES
   github-pages (~> 203)