Bump k3s version to 1.29.0

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 Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 60.97%. Comparing base (9484e36) to head (e9809cd).

Additional details and impacted files

```diff @@ 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](https://app.codecov.io/gh/flyteorg/flyte/pull/5475/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=flyteorg) | Coverage Δ | | |---|---|---| | [unittests-datacatalog](https://app.codecov.io/gh/flyteorg/flyte/pull/5475/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=flyteorg) | `69.31% <ø> (ø)` | | | [unittests-flyteadmin](https://app.codecov.io/gh/flyteorg/flyte/pull/5475/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=flyteorg) | `58.66% <ø> (+0.04%)` | :arrow_up: | | [unittests-flytecopilot](https://app.codecov.io/gh/flyteorg/flyte/pull/5475/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=flyteorg) | `17.79% <ø> (ø)` | | | [unittests-flytectl](https://app.codecov.io/gh/flyteorg/flyte/pull/5475/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=flyteorg) | `67.97% <ø> (ø)` | | | [unittests-flyteidl](https://app.codecov.io/gh/flyteorg/flyte/pull/5475/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=flyteorg) | `79.04% <ø> (ø)` | | | [unittests-flyteplugins](https://app.codecov.io/gh/flyteorg/flyte/pull/5475/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=flyteorg) | `61.78% <ø> (ø)` | | | [unittests-flytepropeller](https://app.codecov.io/gh/flyteorg/flyte/pull/5475/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=flyteorg) | `57.32% <ø> (ø)` | | | [unittests-flytestdlib](https://app.codecov.io/gh/flyteorg/flyte/pull/5475/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=flyteorg) | `65.82% <ø> (ø)` | | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=flyteorg#carryforward-flags-in-the-pull-request-comment) to find out more.

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flyteorg / flyte