Identify dependencies which are signed up for GitHub Sponsors

[DuaneOBrien]

This is arguably out of scope for Mariner as described, but there is enough overlap in methodology that we should discuss adding it. If we don't add it, maybe it's a unique project by itself that uses some shared functionality.

While we interrogate the GitHub API for new issues in the repositories, we could also identify repos that have signed up for GitHub Sponsors.

If I recall correctly, the original version of Mariner did this by:

• checking for the existence of a .github/funding.yml file in the repo
• checking for the existence of a .github/fundint.yml file in the organization

The REST API will return a sponsorable flag for individual users, but it does not appear to return a sponsorable flag for orgs or repos.

The GraphQL API exposes a Sponsorable property that only applies to Orgs or Users. In the past I'd seen where individual projects were signed up for sponsors but the Org or User who owned them were not, but I'm not clear on the current state.

The end goal would be to ask Mariner for a separate, distinct list of "repos that could be sponsored" to provide another mechanism for supporting these projects, beyond identifying issues that match a subset of tags.