fix(zarf-tools): build args for uds zarf tools kubectl version

[emoskito]

Description

Adds a build BUILD_ARG for the kubectl version such that the version returns as expected.

Before:

uds zarf tools kubectl version --client
Client Version: v0.0.0-master+$Format:%H$
Kustomize Version: v5.7.1

After:

./build/uds-arm zarf tools kubectl version --client
Client Version: v1.34.2
Kustomize Version: v5.7.1

Related Issue

Fixes #

Relates to #

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Other (security config, docs update, etc)

Checklist before merging

• Test, docs, adr added or updated as needed
• Contributor Guide Steps followed