Add `packaging` as a required dependency?

[baggiponte]

Add `packaging` as a required dependency?

[fcharras]

The bug was introduced in #648

@jeremiedbb apparently packaging only comes pre-installed with pip when using the conda distribution, otherwise it must be installed explicitly.

In this regard #648 seems like a regression should it be reverted, or still resorting to the package_resources way of doing if packaging is not found at least ?

package_resources has the disadvantage of outputting another warning because direct usage is discouraged, but in this particular case outside of conda distribution it's still the only native package with what is needed to check the dependency tree at runtime it seems.

The possible outcomes I see there would be either

• add packaging as a dependency of skrub
• fallback on the package_resources solution if packaging is not importable
• revert #648

[Vincent-Maladiere]

Thank you @baggiponte and @fcharras for the investigation! Closing this as #712 fixes the issue.