release-notes: structure: update 6.4.0 release notes
#### <sub><sup><a name="5390" href="#5390">:link:</a></sup></sub> feature
* Add `--team` flag for `fly set-pipelines` command #5805
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+#### <sub><sup><a name="5855" href="#5855">:link:</a></sup></sub> fix
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+* Fix tooltip on pipeline names. PR: #5855
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+#### <sub><sup><a name="5504" href="#5504">:link:</a></sup></sub> feature
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+* Refactor existing step structure to simplify introducing new steps. The primary user facing change is step validation messages are different. PR: #5504
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+#### <sub><sup><a name="5729" href="#5729">:link:</a></sup></sub> feature
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+* @tlwr updated the `set_pipeline` step to be used across teams. This is 'experimental' for now, please share your feedback in the [thread](https://github.com/concourse/concourse/discussions/5731). PR: #5729
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+#### <sub><sup><a name="5034" href="#5034">:link:</a></sup></sub> feature
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+* @evanchaoli added [OPA](https://www.openpolicyagent.org/) integration to Concourse to enable policy enforcement. The [RFC #41](https://github.com/concourse/rfcs/pull/41) for the integration is still in progress so is considered 'experimental'. PR: #5034
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+#### <sub><sup><a name="5144" href="#5144">:link:</a></sup></sub> feature
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+* Add support for task.run.user field in containerd runtime. Issue: #5144 PR: #5704
