Add unit tests for authentication and webhook parsing

- Implement tests for basic and bearer authentication headers in `test_auth.py`.
- Create tests for the `EasybillWebhookParser` in `test_webhooks.py`, covering JSON and form-encoded payloads, as well as a generic parse and acknowledgement method.

generated/sync/docs/Login.md

@@ -0,0 +1,39 @@
+# Login
+
+
+## Properties
+
+Name | Type | Description | Notes
+------------ | ------------- | ------------- | -------------
+**id** | **int** |  | [optional] [readonly] 
+**first_name** | **str** |  | [optional] 
+**last_name** | **str** |  | [optional] 
+**display_name** | **str** |  | [optional] [readonly] 
+**phone** | **str** |  | [optional] 
+**email** | **str** |  | [optional] 
+**email_signature** | **str** |  | [optional] 
+**login_type** | **str** |  | [optional] [default to 'ASSISTANT']
+**locale** | **str** |  | [optional] 
+**time_zone** | **str** |  | [optional] 
+**security** | [**LoginSecurity**](LoginSecurity.md) |  | [optional] 
+
+## Example
+
+```python
+from easybill_generated_sync.models.login import Login
+
+# TODO update the JSON string below
+json = "{}"
+# create an instance of Login from a JSON string
+login_instance = Login.from_json(json)
+# print the JSON string representation of the object
+print(Login.to_json())
+
+# convert the object into a dict
+login_dict = login_instance.to_dict()
+# create an instance of Login from a dict
+login_from_dict = Login.from_dict(login_dict)
+```
+[[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
+
+