Add Kubeflow 1.8 Release Page

[Davidnet]

Adding draft of the release page for the website

[Davidnet]

PTAL @DnPlas @jbottum

[DnPlas]

Thanks @Davidnet, just minor nits

[DnPlas]

Thanks @Davidnet !
/lgtm
/assign @thesuperzapper

[annajung]

Thanks @Davidnet
/lgtm

[thesuperzapper]

A minor nit so that it's formatted consistently across the table and past versions:

Suggested change

	<a href="https://github.com/kubeflow/pipelines/releases/tag/2.0.3">2.0.3</a>
	<a href="https://github.com/kubeflow/pipelines/releases/tag/2.0.3">v2.0.3</a>

[chensun]

Noticed this also, but realized that this way it's consistent with the tag that is available.

[chensun]

/lgtm
/approve

[google-oss-prow]

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This pull-request has been approved by: chensun, Davidnet, DnPlas

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[thesuperzapper]

@Davidnet @chensun we also should update the linked ROADMAP.md from the kubeflow/kubeflow repo to reflect that Kubefow 1.8 is now released (This will also require us to update the # anchor referenced on this Kubeflow 1.8 release page).