[Dependency] Bump webrick from 1.8.1 to 1.9.0

Bumps [webrick](https://github.com/ruby/webrick) from 1.8.1 to 1.9.0.
- [Release notes](https://github.com/ruby/webrick/releases)
- [Commits](ruby/webrick@v1.8.1...v1.9.0)

---
updated-dependencies:
- dependency-name: webrick
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Gemfile

@@ -7,7 +7,7 @@ end
 
 gem 'wdm', '>= 0.1.1' if Gem.win_platform?
 
-gem "webrick", "~> 1.8"
+gem "webrick", "~> 1.9"
 
 gem 'html-proofer', "~> 3.19.4"
 

Gemfile.lock

@@ -277,7 +277,7 @@ GEM
       concurrent-ruby (~> 1.0)
     unicode-display_width (1.8.0)
     uri (0.13.0)
-    webrick (1.8.1)
+    webrick (1.9.0)
     yell (2.2.2)
 
 PLATFORMS
@@ -289,7 +289,7 @@ DEPENDENCIES
   github-pages (= 232)
   html-proofer (~> 3.19.4)
   json
-  webrick (~> 1.8)
+  webrick (~> 1.9)
 
 BUNDLED WITH
    2.5.6