Only the attributes written by the last tagger in the tagger list gets written in version 1.0.0

[peterbjorgensen]

Since upgrading dolma to version 1.0.0 I only get the attributes from the last tagger in the list.
I think the problem is here:

dolma/python/dolma/core/runtime.py

Lines 198 to 200 in a74b78a

	# if not set; it will potentially not write to the output stream
	# in case a tagger emits no spans
	attributes_by_stream[tagger_output.path] = {}

tagger_output.path is the same for all the taggers in the list, but attributes_by_stream[tagger_output.path] will be set to empty dictionary when looping through the taggers, leaving only the attributes from the last tagger in the list.
This bug is not present in version 0.9.4.
I would submit a pull request, but I am not sure what these three lines are supposed to fix.