convert pipeline async_button component to vue template

app/assets/javascripts/vue_pipelines_index/components/async_button.js → app/assets/javascripts/vue_pipelines_index/components/async_button.vue

+<script>
 /* eslint-disable no-new, no-alert */
 /* global Flash */
 import '~/flash';
@@ -75,8 +76,10 @@ export default {
         });
     },
   },
+};
+</script>
 
-  template: `
+<template>
   <button
     type="button"
     @click="onClick"
@@ -87,7 +90,6 @@ export default {
     data-placement="top"
     :disabled="isLoading">
     <i :class="iconClass" aria-hidden="true"/>
-      <i class="fa fa-spinner fa-spin" aria-hidden="true" v-if="isLoading" />
-    </button>
-  `,
-};
+    <i class="fa fa-spinner fa-spin" aria-hidden="true" v-if="isLoading"
+  />
+</template>

app/assets/javascripts/vue_shared/components/pipelines_table_row.js

 /* eslint-disable no-param-reassign */
 
-import AsyncButtonComponent from '../../vue_pipelines_index/components/async_button';
+import AsyncButtonComponent from '../../vue_pipelines_index/components/async_button.vue';
 import PipelinesActionsComponent from '../../vue_pipelines_index/components/pipelines_actions';
 import PipelinesArtifactsComponent from '../../vue_pipelines_index/components/pipelines_artifacts';
 import PipelinesStatusComponent from '../../vue_pipelines_index/components/status';

spec/javascripts/vue_pipelines_index/async_button_spec.js

 import Vue from 'vue';
-import asyncButtonComp from '~/vue_pipelines_index/components/async_button';
+import asyncButtonComp from '~/vue_pipelines_index/components/async_button.vue';
 
 describe('Pipelines Async Button', () => {
   let component;