Bump nokogiri from 1.11.6 to 1.13.1 in /docs

Bumps [nokogiri](https://github.com/sparklemotion/nokogiri) from 1.11.6 to 1.13.1.
- [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/v1.11.6...v1.13.1)

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

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

docs/Gemfile.lock

@@ -213,22 +213,15 @@ GEM
       rb-fsevent (~> 0.10, >= 0.10.3)
       rb-inotify (~> 0.9, >= 0.9.10)
     mercenary (0.3.6)
-    mini_portile2 (2.5.2)
-      net-ftp (~> 0.1)
     minima (2.5.1)
       jekyll (>= 3.5, < 5.0)
       jekyll-feed (~> 0.9)
       jekyll-seo-tag (~> 2.1)
     minitest (5.14.4)
     multipart-post (2.1.1)
-    net-ftp (0.1.2)
-      net-protocol
-      time
-    net-protocol (0.1.0)
-    nokogiri (1.11.6)
-      mini_portile2 (~> 2.5.0)
+    nokogiri (1.13.1-aarch64-linux)
       racc (~> 1.4)
-    nokogiri (1.11.6-x86_64-linux)
+    nokogiri (1.13.1-x86_64-linux)
       racc (~> 1.4)
     octokit (4.21.0)
       faraday (>= 0.9)
@@ -236,7 +229,7 @@ GEM
     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)
@@ -260,7 +253,6 @@ GEM
     terminal-table (1.8.0)
       unicode-display_width (~> 1.1, >= 1.1.1)
     thread_safe (0.3.6)
-    time (0.1.0)
     typhoeus (1.4.0)
       ethon (>= 0.9.0)
     tzinfo (1.2.9)