Add missing "version" file in release tarballs

[dims]

In package_final_tarball we generate a version file here:

kubernetes/build/lib/release.sh

Line 531 in 5cdab88

echo "${KUBE_GIT_VERSION}" > "${release_stage}/version"

But in package_node_tarballs and package_server_tarballs we missed doing the same. It's very handy to be able to crack open the tar.gz and immediately tell what the version was cut from, so let's please add it there as well.

/sig release
/sig testing

What type of PR is this?

/kind cleanup

What this PR does / why we need it:

Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:

Does this PR introduce a user-facing change?

NONE

Additional documentation e.g., KEPs (Kubernetes Enhancement Proposals), usage docs, etc.:

[k8s-ci-robot]

This issue is currently awaiting triage.

If a SIG or subproject determines this is a relevant issue, they will accept it by applying the triage/accepted label and provide further guidance.

The triage/accepted label can be added by org members by writing /triage accepted in a comment.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository.

[dims]

/assign @BenTheElder @jeremyrickard @aojea

[dims]

/priority important-soon

[BenTheElder]

/lgtm
/approve
/hold
yeah this is super useful, we should probably include a release note to let people know they can start using this?

[k8s-ci-robot]

LGTM label has been added.

Git tree hash: ca37bb20d6bc1d166db67d57fc7c25fcd4cc3a93

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: BenTheElder, dims

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• build/OWNERS [BenTheElder,dims]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[dims]

/hold cancel