Add `<PopupButton>` component

[deptyped]

<script lang="ts" setup>
import { Popup, PopupButton } from 'vue-tg'

function handleAgreeButton() {
  // ...
}

function handleDisagreeButton() {
  // ...
}
</script>

<template>
  <Popup message="Do you agree?">
    <PopupButton text="Agree" type="ok" @click="handleAgreeButton">
    <PopupButton text="Disagree" type="cancel" @click="handleDisagreeButton">
  </Popup>
</template>