Missing implementation for `send_event` (Mirror issue from Upstream)

[olitomlinson]

Mirroring the issue from Upstream microsoft#32

@famarting

There appears to be a missing implementation for the send_event capability. The placeholder code is commented out. And there is no send_event implementation here

durabletask-python/durabletask/worker.py

Lines 819 to 820 in 4fc38e2

	# elif action_type == "sendEvent":
	# return task.get_name(task.OrchestrationContext.send_event)

This would require implementing in order to deliver the SendEvent capability in the Dapr Python SDK