Dependents should include devDependencies as well

[dgchrt]

Currently, the "Dependents" score in a package's page will not count packages that include it as a devDependency. This gives a false notion of how many other packages depend on a specific package, because a development dependency is nonetheless a dependency.

This issue can lead to false assumptions, in many scenarios. In the worst case, it could even lead to deprecating packages that are "seemingly" not used as much, while they could be potentially being a dependency for many other packages.