feat: fire component's events

    Promised fires 'resolved' event when the promise is resolved,
    fires 'rejected' event when the promise is rejected and
    fires 'pending' event when pending delay time is elapsed.

close posva#311

src/Promised.ts

@@ -1,3 +1,4 @@
+import { watch } from 'vue'
 import {
   defineComponent,
   isVue3,
@@ -24,13 +25,23 @@ export const PromisedImpl = /*#__PURE__*/ defineComponent({
       default: 200,
     },
   },
-
-  setup(props, { slots }) {
+  emits: ['resolved', 'rejected', 'pending'],
+  setup(props, { slots, emit, attrs }) {
     const propsAsRefs = toRefs(props)
     const promiseState = reactive(
       usePromise(propsAsRefs.promise, propsAsRefs.pendingDelay)
     )
 
+    watch(promiseState, (promiseState) =>
+      promiseState.isRejected
+        ? emit('rejected', promiseState.error)
+        : !promiseState.isPending
+        ? emit('resolved', promiseState.data)
+        : promiseState.isDelayElapsed
+        ? emit('pending', promiseState.data)
+        : null
+    )
+
     return () => {
       if ('combined' in slots) {
         return slots.combined!(promiseState)