publish Pepr's controller image to IB

[cmwylie19]

Is your feature request related to a problem? Please describe.

Each release, the updated controller image should be published to IB.

Describe the solution you'd like

• Given a release is created
• When CI runs
• Then dependabot pulls the new image

https://repo1.dso.mil/dsop/opensource/defenseunicorns/pepr/controller/-/issues/4

TODO

• [ ] Get Jeff and Barrett as maintainers (Currently Kim and I)
• [x] README.md
• [ ] Dockerfile
• [ ] hardening_manifest.yaml
• [ ] Update README.md with Acceptance Baseline Criteria (ABC) and Overall Risk Assessment (ORA)
• [ ] Renovate.json

Describe alternatives you've considered

(optional) A clear and concise description of any alternative solutions or features you've considered.

Additional context

Add any other context or screenshots about the feature request here.