fix: rename unmount lifecycles

src/count-down/index.js

@@ -63,7 +63,7 @@ export default createComponent({
     }
   },
 
-  beforeDestroy() {
+  beforeUnmount() {
     this.pause();
   },
 

src/count-down/test/index.spec.js

@@ -174,7 +174,7 @@ test('incomplate format prop', () => {
   expect(wrapper).toMatchSnapshot();
 });
 
-test('pause when destroyed', () => {
+test('pause when unmounted', () => {
   const wrapper = mount(CountDown);
   expect(wrapper.vm.counting).toBeTruthy();
   wrapper.destroy();