12.9.0 Auto-deploy branch dropped some commits from previous auto-deploy

While investigating gitlab-org/gitlab#208255 (comment 295081353), we noticed that:

gitlab-org/gitlab@12ac3894 (dated 2020-02-27 00:06:20) dropped some commits that were in

gitlab-org/gitlab@cf91edbb (dated 2020-02-26 14:06:10). Notice how this version went backwards:

$ git diff cf91edbb8e2..12ac38948be lib/gitlab/markdown_cache.rb
diff --git a/lib/gitlab/markdown_cache.rb b/lib/gitlab/markdown_cache.rb
index 473c7203ead..3dfaec48311 100644
--- a/lib/gitlab/markdown_cache.rb
+++ b/lib/gitlab/markdown_cache.rb
@@ -3,7 +3,7 @@
 module Gitlab
   module MarkdownCache
     # Increment this number every time the renderer changes its output
-    CACHE_COMMONMARK_VERSION        = 19
+    CACHE_COMMONMARK_VERSION        = 18
     CACHE_COMMONMARK_VERSION_START  = 10

     BaseError = Class.new(StandardError)

Using triple-dot (...) instead of double-dot (..) (https://stackoverflow.com/questions/462974/what-are-the-differences-between-double-dot-and-triple-dot-in-git-com), we can see this commit somehow got dropped in the most recent auto-deploy version:

$ git log cf91edbb8e2...12ac38948be lib/gitlab/markdown_cache.rb
commit 5012bcde8d9da95310f4b454fb5935b822ec631f
Author: Heinrich Lee Yu <heinrich@gitlab.com>
Date:   Fri Feb 21 20:17:01 2020 +0800

    Cleanup backend code

    Removed EE::Banzai::Filter::LabelReferenceFilter and
    handled all the EE-specific logic in the EE overrides
    of LabelHelper

/cc: @yorickpeterse, @marin