Preheat the oven to 400 degrees F (200 degrees C). Lightly grease a baking sheet. Combine flour, brown sugar, white sugar, baking powder, cinnamon, ginger, baking soda, and salt together in a bowl. Cut in butter using a pastry cutter until the mixture looks like oatmeal. Add pumpkin, cranberries, sour cream, 3 tablespoons milk, and vanilla extract to the flour mixture and gently combine using a fork. Roll dough out onto a floured surface and form a rectangle. Cut into 10 triangles or squares and place on the prepared baking sheet. Bake in the preheated oven until golden brown, 15 to 20 minutes. Meanwhile, combine powdered sugar and milk in a small bowl until smooth. Set glaze aside. Remove scones from the oven and let cool 10 minutes before drizzling glaze on top. Serve warm.