Update puma requirement from >= 3.11.4, < 6.5.0 to >= 3.11.4, < 6.6.0

Updates the requirements on [puma](https://github.com/puma/puma) to permit the latest version.
- [Release notes](https://github.com/puma/puma/releases)
- [Changelog](https://github.com/puma/puma/blob/master/History.md)
- [Commits](puma/puma@v3.11.4...v6.5.0)

---
updated-dependencies:
- dependency-name: puma
  dependency-type: direct:production
...

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

oxidized-web.gemspec

@@ -26,7 +26,7 @@ Gem::Specification.new do |s|
   s.add_runtime_dependency 'htmlentities',        '~> 4.3'
   s.add_runtime_dependency 'json',                '~> 2.3'
   s.add_runtime_dependency 'oxidized',            '~> 0.26'
-  s.add_runtime_dependency 'puma',                '>= 3.11.4', '< 6.5.0'
+  s.add_runtime_dependency 'puma',                '>= 3.11.4', '< 6.6.0'
   s.add_runtime_dependency 'sinatra',             '>= 1.4.6', '< 5.0'
   s.add_runtime_dependency 'sinatra-contrib',     '>= 1.4.6', '< 5.0'