codependencies

This package allows us to depend on other modules, to force these other modules to upgrade to some minimum version. This allows us to express "co dependency" requirements in cases where this module doesn't strictly speaking depend on another module, but conflicts with some version of that module. We are using this here to depend on deprecated modules that have been merged into this package.

In practice, this means:

1. Packages imported here will not end up in the final binary as nothing imports this package.
2. Modules containing these packages will, unfortunately, be downloaded as "dependencies" of this package.
3. Anyone using this module will be forced to upgrade all co-dependencies.