Automated PR: Standardising Files

[skip ci] This PR will standardise the files we have with out agreed spec in sous-chefs/repo-management.
This repo has been identified by topic(s) of chef-cookbook

.markdownlint-cli2.yaml

@@ -2,3 +2,4 @@ config:
   ul-indent: false # MD007
   line-length: false # MD013
   no-duplicate-heading: false # MD024
+  reference-links-images: false # MD052

CHANGELOG.md

@@ -4,6 +4,8 @@ This file is used to list changes made in each version of the postfix cookbook.
 
 ## Unreleased
 
+Standardise files with files in sous-chefs/repo-management
+
 ## 6.0.14 - *2023-03-20*
 
 Standardise files with files in sous-chefs/repo-management