Button for menu does not have accessible name

**Describe the bug**
The Hamburger menu does not have text inside of it so it currently is announced as "button" by screen readers.

Adding an `aria-label` is one way to improve this. This single attribute will give the button an accessible name.

**To Reproduce**
Steps to reproduce the behavior:
1. Go to index.html
2. Resize viewport to tablet or mobile view
3. Run Lighthouse test or Axe Dev Tools

**Expected behavior**
Pass the audit, button have an accessible name

**Screenshots**

**Desktop (please complete the following information):**
- Firefox
- Mac OS
- Desktop

**Additional context**
Enjoying the process you have! Ill make a PR after Im enabled or its ready to be submitted.

Start in index.html and locate the hamburger menu button shown in the issue. Run Lighthouse or Axe DevTools at the tablet or mobile viewport to confirm the current audit result. Done means the button has an accessible name and passes the accessibility audit.

Written by the indexing model from the issue text.