Bot to bump Eirini automatically

[viovanov]

Acceptance Criteria

• [ ] a bot to bump versions of docker images in the kubecf chart.
• [ ] should be a reusable solution
• [ ] cover all eirini images (staging images, bits, opi, etc)
• [ ] cover all eirinix images (persi, logging bridge, ssh)
• [ ] github actions
• [ ] looks for new semver tags on target docker images

[viovanov]

The eirini image might all be synced with their tags, so we may want to optimize PR counts.

[viovanov]

The github action should monitor a docker repository for new semver tags. Whenever there is a new version, the action should update a configurable yaml file, at a configurable jsonpath. Should keep comments.

[viovanov]

@jandubois will mention a kubecf-tools script that can help with merging yaml files with comments.

[jandubois]

@jandubois will mention a kubecf-tools script that can help with merging yaml files with comments.

I created #1422