Deprecate invoking commands in the old style

Library/Homebrew/cli/parser.rb

@@ -167,6 +167,14 @@ module Homebrew
           @command_name = T.let(T.must(cmd_location.label).chomp("_args").tr("_", "-"), String)
           @is_dev_cmd = T.let(T.must(cmd_location.absolute_path).start_with?(Commands::HOMEBREW_DEV_CMD_PATH),
                               T::Boolean)
+          # We allow this path only from `brew.rb`:
+          if @command_name != "<main>"
+            odeprecated(
+              "`brew #{@command_name}', which does not inherit from from Homebrew::AbstractCommand. This command " \
+              "needs to be refactored, as it is written in a style that",
+              disable_for_developers: false,
+            )
+          end
         end
 
         @constraints = T.let([], T::Array[[String, String]])

Library/Homebrew/extend/kernel.rb

@@ -172,11 +172,13 @@ module Kernel
 
     disable = true if disable_for_developers && Homebrew::EnvConfig.developer?
     if disable || Homebrew.raise_deprecation_exceptions?
+      require "utils/github/actions"
       GitHub::Actions.puts_annotation_if_env_set(:error, message, file:, line:)
       exception = MethodDeprecatedError.new(message)
       exception.set_backtrace(backtrace)
       raise exception
     elsif !Homebrew.auditing?
+      require "utils/github/actions"
       GitHub::Actions.puts_annotation_if_env_set(:warning, message, file:, line:)
       opoo message
     end