Remove automatically installed orphaned dependency at update

[notramo]

Package a-1.0 depends on package b. b is installed automatically, and only a depends on it. Then comes a-1.1 which no longer depends on b (so b is orphaned), but introduces new dependency c. b and c conflicts. In this case, the update of a is aborted due to error. Better handling would be if a dependency of an old version would become orphan, remove it (or maybe remove only if it conflicts with a new dependency of the package that installed it). An example is the Crystal compiler. When they update the LLVM version supported in new Crystal releases, I have to remove Crystal to be able to upgrade.