Fix TypeError in NetCommandFactoryJson.make_get_thread_stack_message() (

microsoft#928)

Set startFrame and levels to 0 if None to avoid TypeError

src/debugpy/_vendored/pydevd/_pydevd_bundle/pydevd_process_net_command_json.py

@@ -917,8 +917,16 @@ def on_stacktrace_request(self, py_db, request):
  # : :type stack_trace_arguments: StackTraceArguments
  stack_trace_arguments = request.arguments
  thread_id = stack_trace_arguments.threadId
- start_frame = stack_trace_arguments.startFrame
- levels = stack_trace_arguments.levels
+
+ if stack_trace_arguments.startFrame:
+ start_frame = int(stack_trace_arguments.startFrame)
+ else:
+ start_frame = 0
+
+ if stack_trace_arguments.levels:
+ levels = int(stack_trace_arguments.levels)
+ else:
+ levels = 0
 
  fmt = stack_trace_arguments.format
  if hasattr(fmt, 'to_dict'):