chore: add dropdown emits (#3237)

Author: zkwolf

components/dropdown/dropdown-button.tsx

@@ -35,6 +35,7 @@ export default defineComponent({
   name: 'ADropdownButton',
   inheritAttrs: false,
   props: DropdownButtonProps,
+  emits: ['click', 'visibleChange', 'update:visible'],
   setup() {
     return {
       configProvider: inject('configProvider', defaultConfigProvider),

components/dropdown/dropdown.tsx

@@ -26,7 +26,9 @@ const Dropdown = defineComponent({
     mouseLeaveDelay: PropTypes.number.def(0.1),
     placement: DropdownProps.placement.def('bottomLeft'),
     onVisibleChange: PropTypes.func,
+    'onUpdate:visible': PropTypes.func,
   },
+  emits: ['visibleChange', 'update:visible'],
   setup() {
     return {
       configProvider: inject('configProvider', defaultConfigProvider),