Bump k3s version to 1.29.0

[eapolinario]

Why are the changes needed?

A user on OSS slack mentioned that they were trying to use RestartPolicy to configure an init container, but that field was not behaving properly in the demo cluster.

What changes were proposed in this pull request?

Bump the version of k3s to 1.29.0, which is the first version of k8s that supports that field in an init container.

How was this patch tested?

I built the demo cluster locally (make -C docker/sandbox-bundled build from the root) and used that to kick off the following workflow (notice the use of restart_policy in the init container):

from flytekit import task, workflow, PodTemplate
from kubernetes.client import V1PodSpec, V1Container

@task(
    pod_template=PodTemplate(
        pod_spec=V1PodSpec(
            containers=[
                V1Container(
                    name="primary",
                )
            ],
            init_containers=[
                V1Container(
                    image="alpine",
                    name="init",
                    command=["/bin/sh"],
                    args=["-c", 'echo "I\'m a customizable init container"'],
                    restart_policy="Always",
                )
            ],
        ),
    )
)
def t():
    ...


@workflow
def wf():
    t()

Setup process

Screenshots

Check all the applicable boxes

• I updated the documentation accordingly.
• All new and existing tests passed.
• All commits are signed-off.

Related PRs

Docs link

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 60.97%. Comparing base (9484e36) to head (e9809cd).
Report is 135 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #5475      +/-   ##
==========================================
+ Coverage   60.96%   60.97%   +0.01%     
==========================================
  Files         793      793              
  Lines       51331    51331              
==========================================
+ Hits        31293    31299       +6     
+ Misses      17153    17147       -6     
  Partials     2885     2885              

Flag	Coverage Δ
unittests-datacatalog	69.31% <ø> (ø)
unittests-flyteadmin	58.66% <ø> (+0.04%)	⬆️
unittests-flytecopilot	17.79% <ø> (ø)
unittests-flytectl	67.97% <ø> (ø)
unittests-flyteidl	79.04% <ø> (ø)
unittests-flyteplugins	61.78% <ø> (ø)
unittests-flytepropeller	57.32% <ø> (ø)
unittests-flytestdlib	65.82% <ø> (ø)

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