feat: Add markdown type in Mimes (#10052)

Author: neznaika0

app/Config/Mimes.php

@@ -481,6 +481,10 @@ class Mimes
             'model/stl',
             'application/octet-stream',
         ],
+        'md' => [
+            'text/markdown',
+            'text/plain',
+        ],
     ];
 
     /**

user_guide_src/source/changelogs/v4.8.0.rst

@@ -215,6 +215,8 @@ Message Changes
 Changes
 *******
 
+- **Config:** Added the ``md`` key for ``Config\Mimes::$mimes`` for Markdown files.
+
 ************
 Deprecations
 ************

user_guide_src/source/installation/upgrade_480.rst

@@ -66,7 +66,8 @@ and it is recommended that you merge the updated versions with your application:
 Config
 ------
 
-- @TODO
+- app/Config/Mimes.php
+    - ``Config\Mimes::$mimes`` added a new key ``md`` for Markdown files.
 
 All Changes
 ===========