(PA-9117) Add Puppet 9 support

[tvpartytonight]

Summary

• Widen the puppet version_requirement in metadata.json to >= 8.0.0 < 10.0.0 so this module declares compatibility with Puppet 9
• Add a CHANGELOG.md entry noting Puppet 9 support

Ref: PA-9117

🤖 Generated with Claude Code

[jst-cyr]

@tvpartytonight : Shouldn't this also add the tests for Puppet 9?

I'm not sure if it applies to this module completely, but here's an example of "Puppet 9 support" that the Unicorn team did for the Kubernetes module: https://github.com/puppetlabs/puppetlabs-kubernetes/pull/723/changes#diff-b803fcb7f17ed9235f1e5cb1fcd2f5d3b2838429d4368ae4c57ce4436577f03f

Might even be able to do some validation with PDK to see if the module has the right Ruby syntax and see if anything needs updating.