Need to fix automatic builds on Docker Hub

[wch]

Automated builds on Docker Hub are no longer working properly. There are two problems that need to be addressed:

• Due to Docker Hub's recent security breach (1, 2), Docker Hub removed its access to my GitHub account. Re-authorizing appears to need read and write access to all of the repositories I have access to, including all the organizations I'm a member of, and I don't think that providing that access is worth the risk.
• Docker Hub's repository links no longer work, so the chained builds do not happen automatically: No more automatic rebuilds on upstream images pushes? docker/hub-feedback#1717

Screenshot of the permissions Docker Hub wants:

[wch]

I've decided to give up on this and instead build the images on a local machine and push them to Docker Hub.