feat: add OIDC custom property

[gogoyan11]

Resolves #N/A (new feature — no existing issue)

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Before the change?

• There was no way to manage which repository custom properties are included in GitHub Actions OIDC tokens at the organization level. The GitHub API added new endpoints for this in API version 2026-03-10 (changelog), but the Terraform provider had no corresponding resources.

After the change?

• Added a new resource github_actions_organization_oidc_custom_property_inclusion that allows managing individual custom property inclusions in OIDC tokens for an organization (create, read, delete, import).
• Added a new data source github_actions_organization_oidc_custom_property_inclusions that lists all custom properties currently included in OIDC tokens for an organization.
• Uses raw HTTP requests with X-GitHub-Api-Version: 2026-03-10 header since the go-github library does not yet have bindings for these endpoints.

Pull request checklist

• Schema migrations have been created if needed (example)
• Tests for the changes have been added (for bug fixes / features)
• Docs have been reviewed and added / updated if needed (for bug fixes / features)

Does this introduce a breaking change?

Please see our docs on breaking changes to help!

• Yes
• No

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[github-actions]

👋 Hi! Thank you for this contribution! Just to let you know, our GitHub SDK team does a round of issue and PR reviews twice a week, every Monday and Friday! We have a process in place for prioritizing and responding to your input. Because you are a part of this community please feel free to comment, add to, or pick up any issues/PRs that are labeled with Status: Up for grabs. You & others like you are the reason all of this works! So thank you & happy coding! 🚀

[deiga]

Thanks for the contribution! We don't accept raw REST API into the provider. Please submit a PR to go-github to get the API added there :)