github: call github API twice for organisation repos

Created by: asdine

Currently, the Github API doesn't return internal repos when calling it with the "all" type. We need to call it twice, once with the "all" type and once with the "internal" type. However, since we don't have any guarantee that this behavior will always remain the same and that Github will never fix this issue, we need to deduplicate the results before sending them to the results channel.