[listepo]

Adds .github/FUNDING.yml so the Sponsor button links to GitHub Sponsors (listepo), Open Collective (pyrlyn) and Patreon (pyrlyn).

Docs

• How it works: GitHub reads .github/FUNDING.yml and shows these links in the repository's Sponsor dialog. A repo-level file overrides the org default from the .github repo.
• Enable: merge this PR and tick Settings -> General -> Features -> Sponsorships.
• Disable: untick Sponsorships, or remove/comment out lines in this file.
• Test: open the repository page and click Sponsor; all three links should appear.
• Limitations: the Open Collective link works only after the pyrlyn collective is approved; the button is shown only when Sponsorships is enabled.