Allow Banner to be rendered as a section

[khiga8]

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Please read this description carefully. If you feel there is anything unclear or missing, please ask for updates.

What are you trying to accomplish?

I want to allow Banner to be rendered as a <section>, so I have an option to render it as a region landmark (via <section aria-labelledby>), without explicitly setting a role.

Integration

No

List the issues that this change affects.

Closes #2540

Risk Assessment

• Low risk the change is small, highly observable, and easily rolled back.
• Medium risk changes that are isolated, reduced in scope or could impact few users. The change will not impact library availability.
• High risk changes are those that could impact customers and SLOs, low or no test coverage, low observability, or slow to rollback.

What approach did you choose and why?

There may be more updates incoming but this is a non-breaking, baby step change and it shouldn't impact any existing Banner instances.

Merge checklist

• Added/updated tests
• Added/updated documentation
• Added/updated previews (Lookbook)
• Tested in Chrome
• Tested in Firefox
• Tested in Safari
• Tested in Edge

[changeset-bot]

🦋 Changeset detected

Latest commit: 4d282e1

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@primer/view-components	Patch

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[keithamus]

Great stuff! 🚢

[khiga8]

@keithamus I do not permission to merge so please merge whenever :)