Support pinning container image by digest (repo@sha256) in values

[skrawani]

It would be helpful to pin the Qdrant container image by digest for reproducible deploys. Today the chart seems to only render repository:tag.

• Expected: when a digest is provided, render repository@sha256:<digest> and prefer it over tag if both are set.
• Proposal: add image.digest to values and adjust templates to use it when present (fall back to repository:tag otherwise).

Example values:

image:
  repository: docker.io/qdrant/qdrant
  tag: v1.15.4
  digest: sha256:<digest>

Expected render:

image: docker.io/qdrant/qdrant@sha256:<digest>

[d-haus]

Also having issues with this.
The line 144 in statefulset.yaml prevents any non semver compatible tags.
path: "{{- if semverCompare ">=1.7.3" ($.Values.image.tag | default $.Chart.AppVersion) -}}/readyz{{else}}/{{end}}"
Especially when there are tags that just contain a digest, like sha256:94728574965d17c6485dd361aa3c0818b325b9016dac5ea6afec7b4b2700865f
Would appreciate a way to pin a digest without getting semver issues.