closes #21

[codewizard13]

🛠️ Fixes Issue : #21

👨‍💻 Changes:

• add a contribution section in the readme
• list all of our contributors in there using the github API
• use contrib.rocks generated image url for this
• align everything in the center

<a href="https://github.com/osbc2022/to-do-list/graphs/contributors">
  <img src="https://contrib.rocks/image?repo=osbc2022/to-do-list" />
</a>

✔️ Check List

• My code follows the code style of this project.
• This PR does not contain plagiarized content.
• The title of my pull request is a short description of the requested changes.

📷 Screenshots

[osbc2022]

Great !! 🤩