Oracle 12c vs DockerHub Credentials in Public PRs

Hello. I am a maintainer of a framework called Quill, that uses Travis for our builds. Recently I have been trying to integrate the Oracle 12c DockerHub container into our build, however, since the official Oracle 12c container (here) for this database requires DockerHub credentials, and it is impossible to use DockerHub credentials from public-PRs (as stated here), the official Oracle 12c container is effectively unusable during most code contributions. This makes for a very bad developer experinece, particularily for new contributors. I reached out to the Oracle people on their Github area here, and they would like to have a external conversation with Travis personnel about alternative solutions that would allow Oracle 12c to be used on Travis CI without needing to go through DockerHub authorization. I would greatly appreciate if someone from Travis could start this conversation with them, and I think many other open source frameworks would as well (BTW, the Cirrus people have already replied). Please have a look: