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/TimeTracking.md

@@ -0,0 +1,41 @@
+# TimeTracking
+
+
+## Properties
+
+Name | Type | Description | Notes
+------------ | ------------- | ------------- | -------------
+**cleared_at** | **datetime** |  | [optional] 
+**created_at** | **datetime** |  | [optional] [readonly] 
+**date_from_at** | **datetime** |  | [optional] 
+**date_thru_at** | **datetime** |  | [optional] 
+**description** | **str** |  | 
+**hourly_rate** | **float** | Hourly rate in cents (e.g. \"150\" = 1.50€) | [optional] [default to 0.0]
+**id** | **int** |  | [optional] [readonly] 
+**note** | **str** |  | [optional] [default to 'null']
+**number** | **str** | Can be chosen freely | [optional] 
+**position_id** | **int** |  | [optional] 
+**project_id** | **int** |  | [optional] 
+**login_id** | **int** | If omitted or null, the currently active login is used. | [optional] 
+**timer_value** | **int** | Tracked time in minutes | [optional] 
+
+## Example
+
+```python
+from easybill_generated_sync.models.time_tracking import TimeTracking
+
+# TODO update the JSON string below
+json = "{}"
+# create an instance of TimeTracking from a JSON string
+time_tracking_instance = TimeTracking.from_json(json)
+# print the JSON string representation of the object
+print(TimeTracking.to_json())
+
+# convert the object into a dict
+time_tracking_dict = time_tracking_instance.to_dict()
+# create an instance of TimeTracking from a dict
+time_tracking_from_dict = TimeTracking.from_dict(time_tracking_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)
+
+