Fix "attention" link

[andrew-demb]

After dropping the section about deploying to Heroku, there is left an unchanged "attention" link in "How to use" section.

All Submissions

• [x] Have you followed the guidelines in our Contributing document?
• [x] Have you checked to ensure there aren't other open Pull Requests for the same update/change?

New Feature Submissions

1. [x] Does your submission pass tests?
2. [x] Have you lint your code locally prior to submission?

Changes to Core Features

• [x] Have you added an explanation of what your changes do and why you'd like us to include them?
• [x] Have you written new tests for your core changes, as applicable?
• [x] Have you successfully ran tests with your changes locally?

[vercel[bot]]

@andrew-demb is attempting to deploy a commit to the ashutosh00710's projects Team on Vercel.

A member of the Team first needs to authorize it.