Temporarily pin kubectl version

[patrobinson]

Description

main build is failing

The latest k8s release hasn't been uploaded to the GCP bucket yet, which is causing our build to fail

Changes

Pin the k8s version for now

Testing

• Tests have run locally (with go test ./...). Buildkite employees may check this if the pipeline has run automatically.
• Code is formatted (with go fmt ./...)

[moskyb]

i think it probably makes sense to pin this anyway, rather than blindly using whatever the latest k8s is... though i suppose this way, we run the risk of forgetting to update k8s.

either way, ✅ in favour of fixing main

[DrJosh9000]

At the risk of nerd-sniping you, is there a way we could make dependabot bump this?

[DrJosh9000]

Suggested change

	"https://storage.googleapis.com/kubernetes-release/release/$VERSION/bin/linux/$TARGETARCH/kubectl"
	"https://storage.googleapis.com/kubernetes-release/release/${K8_VERSION}/bin/linux/$TARGETARCH/kubectl"

[wolfeidau]

@patrobinson @DrJosh9000 can we just pull this out of a container so we get pinning and a supported source?

wget binary feels not ideal.

[patrobinson]

@DrJosh9000 to do that I think we'd want to switch to using the container registry.k8s.io/kubectl:v1.31.1 instead of downloading the binary via wget, that way I think dependabot will be able to recognise the version and update it?

FROM registry.k8s.io/kubectl:v1.31.1 AS kubectl

FROM base AS runtime

ARG TARGETOS
ARG TARGETARCH

COPY --from=kubectl /kubectl /bin/kubectl