os/mac/version: add unsupported_release? helper

Library/Homebrew/github_runner_matrix.rb

@@ -114,7 +114,7 @@ class GitHubRunnerMatrix
 
     MacOSVersions::SYMBOLS.each_value do |version|
       macos_version = OS::Mac::Version.new(version)
-      next if macos_version.outdated_release? || macos_version.prerelease?
+      next if macos_version.unsupported_release?
 
       spec = MacOSRunnerSpec.new(
         name:    "macOS #{version}-x86_64",

Library/Homebrew/os/mac/version.rb

@@ -72,6 +72,11 @@ module OS
         self >= HOMEBREW_MACOS_NEWEST_UNSUPPORTED
       end
 
+      sig { returns(T::Boolean) }
+      def unsupported_release?
+        outdated_release? || prerelease?
+      end
+
       # For {OS::Mac::Version} compatibility.
       sig { returns(T::Boolean) }
       def requires_nehalem_cpu?