Use latest or tag when building image

[jeanlaurent]

1. Replaced type=ref,event=branch with
   type=raw,value=latest,enable={{is_default_branch}}
   • This will tag builds from the main branch (default
     branch) as "latest" instead of "main"
2. Kept type=ref,event=tag
   - This ensures version tag builds (like v1.0.0) are tagged
   with their actual tag name

Now when:

• Building from the main branch → image will be tagged as
  latest
• Building from a version tag like v1.0.0 → image will be
  tagged as v1.0.0