Set a default reviewer

GitHub has the ability to set the default reviewer using a CODEOWNERS file.

Code owners are automatically requested for review when someone opens a pull request that modifies code that they own. When someone with admin permissions has enabled required reviews, they can optionally require approval from a code owner.

To use a CODEOWNERS file, create a new file called CODEOWNERS in the root, docs/, or .github/ directory of the repository, in the branch where you'd like to add the code owners.

You should add .github/CODEOWNERS file with users to send PR to.

Example to send PR for any change on codebase represented by *:

## code changes will send PR to following users
* @option1-user1 @option1-user2 @option2-your-org/team-name

See: https://docs.github.com/en/enterprise/2.18/user/github/creating-cloning-and-archiving-repositories/about-code-owners

Note: .github/CODEOWNERS should be in main branch to be effective.