DUANESBURG — Three rural school districts will come together for a job fair this week, trying to address staff shortages as a new school year looms just three months away.The superintendents of the Duanesburg, Schoharie and Sharon Springs school districts say the much-publicized labor shortage in upstate New York is real and it extends into the educational sector. Rural school districts, they say, have a tougher time addressing it than their suburban counterparts.The situation was identified as a growing problem and attempts were initiated at the state level to address it long before the COVID pandemic sparked what has come to…