Add bin/packs lint_deprecated_references command

[alexevanczuk]

Note that this will be changed to lint_package_todo once packwerk 3.x is released.

This is extracted from Gusto's codebase. The idea is that we want to ensure that no one receives a noisy diff when running bin/packwerk update-deprecations. We use this in our CI suite.

[alexevanczuk]

At Gusto, we can configure this like this:

--- /dev/null
+++ b/config/use_packwerk.rb
@@ -0,0 +1,7 @@
+require 'gusto_packwerk'
+
+module GustoPackwerk
+  UsePackwerk.configure do |config|
+    config.on_deprecated_references_lint_failure = -> (output) { Private.post_buildkite_annotation(output) }
+  end
+end

I don't love this exactly... some alternative ideas were to have this method return a Result type with the output, and we could just do whatever we want with that result. However, I liked the idea that we can use the vanilla bin stub (bin/packs lint_deprecated_references) without needing to orchestrate anything else.