fixed public assets folder and index.html file not being sent if hosted on vercel

[spicybirsge]

Checklist:

• I have read freeCodeCamp's contribution guidelines.
• My pull request has a descriptive title (not a vague title like Update index.md)

When hosting on vercel, the index.html file and the public file don't get send and return 404 even though it works locally, but with this change it would work both ways.