Bump nokogiri from 1.7.1 to 1.10.4 in /site/jekyll (#911)

Bumps [nokogiri](https://github.com/sparklemotion/nokogiri) from 1.7.1 to 1.10.4.
- [Release notes](https://github.com/sparklemotion/nokogiri/releases)
- [Changelog](https://github.com/sparklemotion/nokogiri/blob/master/CHANGELOG.md)
- [Commits](sparklemotion/nokogiri@v1.7.1...v1.10.4)

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

Author: dependabot[bot]

site/jekyll/Gemfile.lock

@@ -39,12 +39,12 @@ GEM
       rb-inotify (>= 0.9)
       rb-kqueue (>= 0.2)
     maruku (0.7.0)
-    mini_portile2 (2.1.0)
+    mini_portile2 (2.4.0)
     multi_json (1.12.1)
-    nokogiri (1.7.1)
-      mini_portile2 (~> 2.1.0)
-    nokogiri (1.7.1-x64-mingw32)
-      mini_portile2 (~> 2.1.0)
+    nokogiri (1.10.4)
+      mini_portile2 (~> 2.4.0)
+    nokogiri (1.10.4-x64-mingw32)
+      mini_portile2 (~> 2.4.0)
     nokogumbo (1.4.10)
       nokogiri
     parslet (1.5.0)