Fix indent in Action Cable changelog entry [ci skip]

actioncable/CHANGELOG.md

@@ -12,12 +12,13 @@
     ActionCable-PID-42
     (2 rows)
     */
-     ```
+    ```
 
-     *Sergey Ponomarev*
+    *Sergey Ponomarev*
 
 *   Subscription confirmations and rejections are now logged at the `DEBUG` level instead of `INFO`.
 
     *DHH*
 
+
 Please check [6-0-stable](https://github.com/rails/rails/blob/6-0-stable/actioncable/CHANGELOG.md) for previous changes.