Update top-level docs to the next-to-last version if the last version is being reverted

[ericmj]

No description provided.

[idyll]

Can this include a flag or indication of the nature of the issue with the previous package.

I am hoping to use this to add additional scanning beyond just out of date and instead fail builds when a package you are using contains a known security issue.

[ericmj]

This is only for docs. You can only revert packages for up to one hour after its initial release so it's unlikely that's for security reasons.

[ericmj]

This will not be needed when we move to the new hexdocs service.