Looks like this was added to github.com around March 2022 and Enterprise Server in May 2022.
It allows other repositories in the same organization or enterprise to access actions in said repository

Endpoints:
GET /repos/{owner}/{repo}/actions/permissions/access
PUT /repos/{owner}/{repo}/actions/permissions/access

I imagine this should be added as repos_actions_permissions_access.go 🤔

Additional Links & References

github/roadmap#74
https://docs.github.com/en/enterprise-cloud@latest/actions/creating-actions/sharing-actions-and-workflows-with-your-enterprise