Add tonyxrmdavidson to model-registry as maintainer

[tonyxrmdavidson]

Description

New Open Data Hub Member Requirements

• [ ] New members have reviewed and acknowledged the Open Data Hub:
  • Code of Conduct
  • Contribution Guide
  • Community Membership Guidelines
• [ ] Enabled 2FA on their GitHub account

Pull Request Requirements

• [ ] New members are added in alphabetical order
• [ ] Only one new member change per commit (if you add two members separate it in two commits
• [ ] For individual user changes: Commit message format Add <USERNAME> to <opendatahub-io, mlops-sig, ...>.
• [ ] For new team requests: Commit message format Create <TEAMNAME>. If the new team consists solely of existing members, you may
• [ ] New GitHub team requests are from an existing opendatahub-io member who will function as the maintainer of the team. Each additional member will follow the same requirements for adding new members

[taneem-ibrahim]

/lgtm