Enhance repository to handling optional mention / at sign in repository owner field

[andyfeller]

Overview

Thanks for feedback from @papaissad as it appears there is an opportunity to enhance the validation or parse logic as there might be a use cases where someone uses the mention / at sign form of an organization for the repository owner.

In https://github.com/papaissad-sandbox-org/issueops-repo/issues/12#issuecomment-1442139959, the validation logic failed the request because it doesn't strip the @ before using the input in subsequent logic. This should be easy enough to fix 💪

Action Items

• [ ] Enhance parsing or validation logic to handle optional @