[Vuejs]-@vue.cli 4.2.3 Add Expires headers

addding an expires header is not done in your code but in your .htaccess if you’re using apache server for example.
Gtmatrix also provided an article on how you can do this.
https://gtmetrix.com/serve-static-assets-with-an-efficient-cache-policy.html
So you don’t need to worry in your code as there is not a plugin to do this in Vuejs or any framework