Protestors march along Saginaw Street demanding clean water outside of Flint City Hall in Flint, Mich. on Wednesday Oct. 7, 2015. Christian Randolph | MLive.com Summer is approaching quickly, and with it, warmer weather. Generally this is a pleasant transition from a cold winter, but the residents of Flint, Michigan may have a reason to dread the upcoming season. The transition to Spring may see an uptick in the number of cases of Legionnaires’ disease. Bacteria thrive in warmer water, and Flint has had a terrible problem with bacteria in the past year. Second to lead exposure, Legionella bacteria has been…