Use second-level headings

Author: janbuchar

docs/04-upgrading/upgrading_to_v20.md

@@ -5,27 +5,27 @@ title: Upgrading to v2.0
 
 This page summarizes most of the breaking changes between Apify Python SDK v1.x and v2.0.
 
-# Storages
+## Storages
 
 The SDK now uses [crawlee](https://github.com/apify/crawlee-python) for local storage emulation. This change should not affect intended usage (working with `Dataset`, `KeyValueStore` and `RequestQueue` classes from the `apify.storages` module or using the shortcuts exposed by the `Actor` class) in any way.
 
 Removing the `StorageClientManager` class is a significant change. If you need to change the storage client, use `crawlee.service_container` instead.
 
-# Configuration
+## Configuration
 
 The `apify.Configuration` class now uses `pydantic_settings` to load configuration from environment variables. This eliminates the need for the helper functions which handled environment variables in `apify._utils`.
 
 Attributes suffixed with `_millis` were renamed to remove said suffix and have the `datetime.timedelta` type now.
 
-# Actor
+## Actor
 
 The `Actor.main` method has been removed as it brings no benefits compared to using `async with Actor`.
 
-# Scrapy integration
+## Scrapy integration
 
 The `apify.scrapy.utils.open_queue_with_custom_client` function is not necessary anymore and has been removed.
 
-# Subpackage visibility
+## Subpackage visibility
 
 The following modules were made private: