[Doc] libopenmpt: Update changelog.

git-svn-id: https://source.openmpt.org/svn/openmpt/branches/OpenMPT-1.28@24378 56274372-70c3-4bfc-bfc3-4c3a0b034d27

Author: manxorist

libopenmpt/dox/changelog.md

@@ -8,6 +8,9 @@ is just a high-level summary.
 ### libopenmpt 0.4.52-pre
 
  *  mpg123: Update to v1.33.3 (2025-10-05).
+ *  minimp3: Update to fork
+    <https://github.com/manxorist/minimp3/releases/tag/openmpt-2024-08-15-v4>
+    commit 2116754771b79347ad2f39127abace2a093c383e (2024-08-15).
 
 ### libopenmpt 0.4.51 (2025-09-06)