docs: add v5 migration guide

docs/migration/v4.md

@@ -21,7 +21,7 @@ The function creates and manages its own **dedicated session** internally, yield
         user.balance += 100
 
     # With a custom lock mode
-    async with lock_tables(session, [Order], mode=LockMode.EXCLUSIVE):
+    async with lock_tables(session=session, tables=[Order], mode=LockMode.EXCLUSIVE):
         await process_order(session, order_id)
     ```
 
@@ -35,6 +35,6 @@ The function creates and manages its own **dedicated session** internally, yield
         user.balance += 100
 
     # With a custom lock mode
-    async with lock_tables(session_maker, [Order], mode=LockMode.EXCLUSIVE) as session:
+    async with lock_tables(session_maker=session_maker, tables=[Order], mode=LockMode.EXCLUSIVE) as session:
         await process_order(session, order_id)
     ```