We have a GitHub discussion open about that here:
https://github.com/meltano/meltano/discussions/6687
The current plan is to not give our repositories the "Hacktoberfest" topic, nor add the "Hacktoberfest" label to any issues, but if a quality contribution is made and the contributor would like the PR to be labelled "Hacktoberfest", then we can add the label. We hope that this will minimize low-quality contributions from people who are purely looking to rack up Hacktoberfest PRs, while still rewarding our valued contributors.