Gov. Gavin Newsom’s signing of the $308 billion state budget Thursday evening handed California’s struggling cannabis industry long-sought tax relief. The state eliminated the cultivation tax on growers and capped the excise tax at point of sale at 15% for three years, moves hailed by industry advocates as a victory after a prolonged push in Sacramento to lighten the tax burden on the legal trade. Growers have felt the pinch over the last two years…