deb: fix changelog entry format

Follows #281

Author: DifferentialOrange

debian/changelog

@@ -5,17 +5,17 @@ python3-tarantool (0.12.0-0) unstable; urgency=medium
     This release introduces the support of `fetch_schema` connection
     option to disable schema fetch and various fixes.
 
-    ### Breaking changes
+    ## Breaking changes
 
     This release should not break any existing behavior.
 
-    ### New features
+    ## New features
     - `fetch_schema` parameter for a connection (#219).
 
-    ### Bugfixes
+    ## Bugfixes
     - Error code on socket error (#279).
 
-    ### Thanks
+    ## Thanks
     We want to thank @bekhzod91 for a bugfix contribution.
 
  -- Georgy Moiseev <[email protected]>  Mon, 13 Feb 2023 11:43:30 +0300