Chocolate Zucchini Cupcakes

Ingredients
1-1/4 cups butter, softened
1-1/2 cups sugar
2 large eggs, room temperature
1 teaspoon vanilla extract
2-1/2 cups all-purpose flour
3/4 cup baking cocoa
1 teaspoon baking powder
1 teaspoon baking soda
1/2 teaspoon salt
1/2 cup plain yogurt
1 cup grated zucchini
1 cup grated carrots
1 can (16 ounces) chocolate frosting