Add a CODEOWNERS file to this repo

[parispittman]

The Contributor Experience Workgroup is currently working on a swiftlang/swift-org-website#1269 and other initiatives that require this repository to have a .github/CODEOWNERS file. We have drawn up a template with required patterns in the /repo-templates project. Please record the code owners of this repository in such a CODEOWNERS file, so that the definition of a Code Owner applies it.

We're here for any questions or help needed! Reach out on the forums or directly.

[ktoso]

Thanks for the ping! Done in #518