Fix misformatted changelog

It's not yet clear why it was misformatted, but while we figure it out
it's better to patch those.

Being tracked on pulp/plugin_template#907

[noissue]

CHANGES.md

@@ -32,7 +32,7 @@ No significant changes.
 
 ---
 
-# ## 3.57.0 (2024-08-07) {: #3.57.0 }
+## 3.57.0 (2024-08-07) {: #3.57.0 }
 
 ### REST API {: #3.57.0-rest-api }