Pin Docker image versions in all Kubernetes deployments

[mgajek-cern]

Summary:
Currently, some Kubernetes manifests reference images with the latest tag, e.g.:

image: rucio/rucio-clients:latest

Issue:
Using latest can lead to unpredictable behavior, breaking reproducibility and stability across environments.

Proposed change:

• Pin all container images in Kubernetes deployments and pods to specific versions, e.g.:

image: rucio/rucio-clients:1.29.0

Rucio Docker images: https://hub.docker.com/u/rucio

Benefits:

• Ensures consistent, reproducible deployments.
• Avoids accidental breaking changes from automatic upgrades.
• Simplifies debugging and testing.

[rdimaio]

I agree with this, but we should make sure that we don't fall behind on updates. I guess we should set up some automatic CI testing that checks everything works as expected, and once that's up we can also add dependabot

[mgajek-cern]

I agree with this, but we should make sure that we don't fall behind on updates. I guess we should set up some automatic CI testing that checks everything works as expected, and once that's up we can also add dependabot

We have an issue for this now #46

NOTE: Dependabot has support for Kubernetes YAML manifests (https://github.blog/changelog/2022-11-16-dependabot-version-updates-for-docker-image-tags-in-kubernetes-manifests/).