Upgrade jobset SDK version to v0.7.3

[Electronic-Waste]

What this PR does / why we need it:

Since we use jobset v0.7.3 in the manifest:

trainer/manifests/third-party/jobset/kustomization.yaml

Lines 1 to 6 in 0b765d6

	apiVersion: kustomize.config.k8s.io/v1beta1
	kind: Kustomization
	resources:
	- https://github.com/kubernetes-sigs/jobset/releases/download/v0.7.3/manifests.yaml

We'd better upgrade the jobset SDK version to v0.7.3 as well.

Which issue(s) this PR fixes (optional, in Fixes #<issue number>, #<issue number>, ... format, will close the issue(s) when PR gets merged):
Fixes #

Checklist:

• Docs included if any changes are user facing

[Electronic-Waste]

/cc @kubeflow/wg-training-leads @astefanutti

[astefanutti]

LGTM, thanks!

[andreyvelich]

Thanks for this @Electronic-Waste!
We should also bump it to v0.8.0 once it is ready since it has DependsOn API support:
kubernetes-sigs/jobset#774

[Electronic-Waste]

@andreyvelich SGTM.I'll create another issue tracking that.

[tenzen-y]

@andreyvelich SGTM.I'll create another issue tracking that.

I agree with you

[tenzen-y]

/lgtm
/approve

[google-oss-prow]

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[tenzen-y]

Thanks for this @Electronic-Waste! We should also bump it to v0.8.0 once it is ready since it has DependsOn API support: kubernetes-sigs/jobset#774

This will take a little more time