feat: Add a Code of Conduct

[BekahHW]

• add CODE_OF_CONDUCT.md file in the root directory of your project.

GitHub has some templates you can use: https://docs.github.com/en/communities/setting-up-your-project-for-healthy-contributions/adding-a-code-of-conduct-to-your-project#adding-a-code-of-conduct-using-a-template