update python (does not work yet)

I get a few errors:
```
FAILED tests/test_chatlist_events.py::test_delivery_status - AttributeError: 'dict' object has no attribute 'kind'
FAILED tests/test_chatlist_events.py::test_delivery_status_failed - AttributeError: 'dict' object has no attribute 'kind'
FAILED tests/test_chatlist_events.py::test_multidevice_sync_chat - AttributeError: 'dict' object has no attribute 'kind'
FAILED tests/test_chatlist_events.py::test_download_on_demand - AttributeError: 'dict' object has no attribute 'kind'
FAILED tests/test_chatlist_events.py::test_imap_sync_seen_msgs - AttributeError: 'dict' object has no attribute 'kind'
```

deltachat-rpc-client/src/deltachat_rpc_client/const.py

@@ -61,6 +61,7 @@ class EventType(str, Enum):
     WEBXDC_INSTANCE_DELETED = "WebxdcInstanceDeleted"
     CHATLIST_CHANGED = "ChatlistChanged"
     CHATLIST_ITEM_CHANGED = "ChatlistItemChanged"
+    TEST_CHECKPOINT_EVENT = "TestCheckpointEvent"
 
 
 class ChatId(IntEnum):

deltachat-rpc-client/src/deltachat_rpc_client/rpc.py

@@ -6,10 +6,12 @@ import logging
 import os
 import subprocess
 import sys
-from queue import Empty, Queue
+from queue import Queue
 from threading import Event, Thread
 from typing import Any, Iterator, Optional
 
+from .const import EventType
+
 
 class JsonRpcError(Exception):
     pass
@@ -190,12 +192,11 @@ class Rpc:
 
     def clear_all_events(self, account_id: int):
         """Removes all queued-up events for a given account. Useful for tests."""
-        queue = self.get_queue(account_id)
-        try:
-            while True:
-                queue.get_nowait()
-        except Empty:
-            pass
+        id = self.trigger_checkpoint_event(account_id)
+        while True:
+            event = self.wait_for_event(account_id)
+            if event.kind == EventType.TEST_CHECKPOINT_EVENT and event.id == id:
+                break
 
     def __getattr__(self, attr: str):
         return RpcMethod(self, attr)