Vue JS Typescript Component support for $auth plugin

Questions
1

When using Typescript components in VueJS, we have to tell Typescript that a plugin exists and what type it is for the TS compiler to play nice. A rough example would be:

import SomePlugin from './SomePlugin';

const myPlugin = {
    install(Vue: any) {
        Vue.prototype.$myPlugin = new SomePlugin();
    },
};
export default myPlugin;

How would I create something similar to ensure the $auth plugin plays nicely with the TS compiler?
Currently I am getting compile errors such as property $auth does not exist on type ComponentName.