Pin base images and add Dependabot checks to keep them up to date

[rdimaio]

See: https://docs.docker.com/build/building/best-practices/#pin-base-image-versions

[jainoshika]

Hii @rdimaio,

Thanks for opening this issue. I’m new to Docker and read the docs mentioned above. I want to confirm my understanding and approach before proceeding.

My plan is to:

• Locate all Dockerfiles in the repository
• Replace floating base images with digest pinning (eg. @sha256)
• Add a .github/dependabot.yml entry for Docker so base image updates are handled via PRs

Please let me know if this is what you had in mind.

Thanks!