feat: Add `.vercel` to eslint addon ignores

The `@sveltejs/adapter-vercel` defaults it's output to `.vercel` in the root of the project. The current ignore rules don't ignore this.

Current:
```ts
const ignoresConfig = object.create({
	ignores: common.expressionFromString('["build/", ".svelte-kit/", "dist/"]')
});
```

Happy to fill out a PR if this makes sense to add!