Refs #38357 - Support of ruby version 3.4

Author: sbernhard

.github/matrix.json

@@ -1,3 +1,3 @@
 {
-  "ruby": ["2.7", "3.0"]
+  "ruby": ["2.7", "3.0", "3.1", "3.2", "3.3", "3.4"]
 }

bundler.d/dhcp_isc.rb

@@ -7,3 +7,8 @@
 group :dhcp_isc_kqueue do
   gem 'rb-kqueue'
 end
+
+# these gems were moved out of the default ruby gems in >=3.4
+if RUBY_VERSION >= '3.4'
+  gem 'observer'
+end

smart_proxy.gemspec

@@ -16,10 +16,12 @@ Gem::Specification.new do |s|
   s.add_dependency 'base64'
   s.add_dependency 'json'
   s.add_dependency 'logging'
+  s.add_dependency 'ostruct'
   s.add_dependency 'rack', '>= 1.3'
   s.add_dependency 'rexml', '~> 3.2'
   s.add_dependency 'sd_notify', '~> 0.1'
   s.add_dependency 'sinatra', '~> 2.0'
+  s.add_dependency 'syslog'
   s.add_dependency 'webrick', '~> 1.0'
   s.description = <<~EOF
     Foreman Proxy is used via The Foreman Project, it allows Foreman to manage