Deprecation for joomla/joomla-cms#38511 (#33)

* Update new-deprecations.md

* Moved to correct version

---------

Co-authored-by: Harald <[email protected]>

Author: laoneo

migrations/40-41/new-deprecations.md

@@ -5,8 +5,7 @@ sidebar_position: 2
 New deprecations
 ===============
 All the new deprecations that should be aware of and what you should now be using instead.
-:::caution TODO
 
-This page is unfinished, please use the **Edit this Page** link at the bottom of this page to help make it more useful.
-
-:::
+### libraries/src/Filesystem/Path.php:clean()
+- PR: https://github.com/joomla/joomla-cms/pull/38511
+- Description: Null should not be passed to the clean function, only strings are allowed. This function will throw an exception in version 6.