Release prep v6.4.0

[github-actions]

Automated release-prep through pdk-templates from commit b92c12e.
Please verify before merging:

• last nightly run is green
• Changelog is readable and has no unlabeled pull requests
• Ensure the changelog version and metadata version match

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.

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[GSPatton]

nightly failures aren't caused by failing tests

[GSPatton]

all checks are good. Just need to resolve CLA license test pending