fix: change "frontend" to "vue" in gitignore (#674)

We used to have `frontend`, but now it's `vue`.

Co-authored-by: İlker G. Öztürk <ilkergoktugozturk@gmail.com>

Author: fadeev

starport/templates/app/stargate/.gitignore

@@ -1,4 +1,3 @@
-frontend/node_modules
-frontend/dist
-frontend/.cache
+vue/node_modules
+vue/dist
 secret.yml