Highlight regression bugfixes in changelog (#14474)

scripts/github-changelog.cr

@@ -150,6 +150,9 @@ record PullRequest,
     if labels.includes?("breaking-change")
       io << "**[breaking]** "
     end
+    if regression?
+      io << "**[regression]** "
+    end
     if experimental?
       io << "**[experimental]** "
     end
@@ -235,6 +238,10 @@ record PullRequest,
     labels.includes?("kind:breaking")
   end
 
+  def regression?
+    labels.includes?("kind:regression")
+  end
+
   def experimental?
     labels.includes?("experimental")
   end