CONTRIBUTING.md instructions throws errors

[dimitrisfasoulas]

🐛 Bug Report

CONTRIBUTING.md seems to be copied from another project, and its instructions fail.

Running yarn lint will fail since eslint-config-prettier been updated (separate issue here)

Changing the config so it works, throws 36756 problems

Also running yarn test fails with Usage Error: Couldn't find a script named "test".

To Reproduce

Steps to reproduce the behavior:

Fork or clone the repo,

Follow CONTRIBURING.md instructions and run yarn lint and yarn test

Expected behavior

Both commands should run, without errors.

Run npx envinfo --system --binaries --npmPackages smooth-doc,gatsby,react,react-dom --markdown --clipboard

Paste the results here:

## System:
 - OS: Linux 5.4 Ubuntu 20.04.1 LTS (Focal Fossa)
 - CPU: (12) x64 Intel(R) Core(TM) i7-9750H CPU @ 2.60GHz
 - Memory: 1.56 GB / 7.77 GB
 - Container: Yes
 - Shell: 5.8 - /usr/bin/zsh
## Binaries:
 - Node: 14.15.1 - ~/.nvm/versions/node/v14.15.1/bin/node
 - Yarn: 2.4.1 - ~/.nvm/versions/node/v14.15.1/bin/yarn
 - npm: 7.5.3 - ~/.nvm/versions/node/v14.15.1/bin/npm