chore(deps): bump nokogiri in /images/fluentd/outputs

Bumps [nokogiri](https://github.com/sparklemotion/nokogiri) from 1.18.8 to 1.18.9.
- [Release notes](https://github.com/sparklemotion/nokogiri/releases)
- [Changelog](https://github.com/sparklemotion/nokogiri/blob/main/CHANGELOG.md)
- [Commits](sparklemotion/nokogiri@v1.18.8...v1.18.9)

---
updated-dependencies:
- dependency-name: nokogiri
  dependency-version: 1.18.9
  dependency-type: indirect
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

images/fluentd/outputs/Gemfile.lock

@@ -271,7 +271,7 @@ GEM
       mime-types-data (~> 3.2015)
     mime-types-data (3.2023.1003)
     mini_mime (1.1.5)
-    mini_portile2 (2.8.8)
+    mini_portile2 (2.8.9)
     minitest (5.22.2)
     msgpack (1.8.0)
     multi_json (1.15.0)
@@ -289,7 +289,7 @@ GEM
     net-smtp (0.4.0)
       net-protocol
     netrc (0.11.0)
-    nokogiri (1.18.8)
+    nokogiri (1.18.9)
       mini_portile2 (~> 2.8.2)
       racc (~> 1.4)
     oj (3.16.10)