document the latest release - 1.5

[pritidesai]

Changes

Added the v1.5.0 release section at the top of the Release section.

/kind documentation

Submitter Checklist

As the author of this PR, please check off the items in this checklist:

• Has Docs if any changes are user facing, including updates to minimum requirements e.g. Kubernetes version bumps
• Has Tests included if any functionality added or changed
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• Release notes contains the string "action required" if the change requires additional action from users switching to the new release

Release Notes

NONE

[vdemeester]

/lgtm

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[vdemeester]

/retest