prettier/react no longer needed in .eslintrc.json

When running `npm run lint` from the root of adopt-me, this error shows up:

**"Error: "prettier/react" has been merged into "prettier" in eslint-config-prettier 8.0.0. See: https://github.com/prettier/eslint-config-prettier/blob/main/CHANGELOG.md#version-800-2021-02-21"**

Removing `"prettier/react"` from extends list in `.eslintrc.json` fixes the problem.

Start with .eslintrc.json and inspect the extends list. Run npm run lint from the repository root, remove the obsolete prettier/react entry, and run the lint command again; done means the reported configuration error is gone.

Written by the indexing model from the issue text.