Update deprecated slot syntax

In `./app/assets/javascripts/environments/components/stop_environment_modal.vue`

app/assets/javascripts/environments/components/stop_environment_modal.vue

@@ -60,7 +60,7 @@ export default {
     footer-primary-button-variant="danger"
     @submit="onSubmit"
   >
-    <template slot="header">
+    <template #header>
       <h4 class="modal-title d-flex mw-100">
         Stopping
         <span v-gl-tooltip :title="environment.name" class="text-truncate ml-1 mr-1 flex-fill">

changelogs/unreleased/update-deprecated-slot-syntax-in---app-assets-javascripts-environments-co.yml

+---
+title: Update deprecated slot syntax in ./app/assets/javascripts/environments/components/stop_environment_modal.vue
+merge_request: 32012
+author: Gilang Gumilar
+type: other