burn image versions

[cmdoret]

Use semantic versioning for container tags (git describe can help)
OCI specification does not allow for + in tags

[cmdoret]

burn versions by increasing patch level (incremental numbers)

[cmdoret]

proposal:

For version x.y.z, always keep 3 images
img:x
img:x.y
img:x.y.z

• On standard commits, bump only latest
• On releases, bump all compatible versions

x.y.z is never replaced
x and x.y are always latest compatible patch