add an alpine integration and update example

[FredKSchott]

Changes

• @Princesseuh and I had talked about this a while ago, but never got around to it.
• This adds the new Alpine.js integration that should be good for most users.
• This updates the framework-alpine example to use the new integration.
• Helps to address feedback like this.

Testing

• Tested manually.
• Covered by existing smoke tests.

Docs

• Integration README will be automatically pulled into docs site
• Is there anything that I need to do to get this integration added to the integrations page of docs?
• Is there anything that I need to do to get this integration added to the integrations catalog of www?

[changeset-bot]

🦋 Changeset detected

Latest commit: 4dec898

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

This PR includes changesets to release 1 package

Name	Type
@astrojs/alpinejs	Minor

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