[KubaJadrzak]

Add new category of Issuer Response Codes Mxx, for Merchant Advice Code mapping

[wacaw]

Please update your branch from main — these are already fixed there:

• ruby/setup-ruby was pinned to v1.223.0, which predates Ruby 4.0 and
  rejects it as an unknown version. Now unpinned to @v1.
• rake was pinned to ~> 12.3; rake 12.3.3 does require 'ostruct', which
  is no longer a default gem in Ruby 4.0. Bumped to ~> 13.4.

git fetch origin && git merge origin/main should get CI green.