*: Fix docker-build target

[matej-g]

Signed-off-by: Matej Gera matejgera@gmail.com

• I added CHANGELOG entry for this change.
• Change is not relevant to the end user.

Changes

Fixed the docker-build target, which currently fails always with:

Sending build context to Docker daemon  295.7MB
Step 1/7 : ARG BASE_DOCKER_SHA="97a9aacc097e5dbdec33b0d671adea0785e76d26ff2b979ee28570baf6a9155d"
Step 2/7 : FROM quay.io/prometheus/busybox@sha256:${BASE_DOCKER_SHA}
invalid reference format
make: *** [Makefile:190: docker-build-amd64] Error 1

Presumably caused as a side-effect of #4965. This PR fixes the target to correctly obtain the relevant SHA.

This currently causes publish_main job to fail as well, meaning no images are being published.

Verification

Run docker-build locally and was able to get pass the problematic step.

[wiardvanrij]

Whoops, good catch :D

[kakkoyun]

LGTM