I'm proofreading a text for the magazine, and came across coworking. I prefer to spell it co-working with a hyphen -.
I've looked on Ngrams, wikipedia, and several dictionaries, and as usual with punctuation issues this one's all over the map. People in the office say everyone spells it without a hyphen and that I'm being too picky or old-fashioned.
What are justifications for using or not using a hyphen in coworking/co-working?