[Utils] Add "packaging" to the package dependencies

[nicolasgorrity]

What happened + What you expected to happen

Bug:

The function utils._ensure_shallow_copy makes a direct import of the package packaging. However, the packaging package is not listed in mlforecast python dependencies.

This causes the preprocessing to raise an import error in a minimal working virtual environment where packaging is not already installed.

Expected behavior:

• No import error in a minimally working virtual environment.
• No need to install this dependency manually.

Versions / Dependencies

• python=3.11.5
• mlforecast=0.10.0

Reproduction script

Script to check the issue:

virtualenv venv -p python3.11
source venv/bin/activate
pip install mlforecast
pip show packaging

Output:

WARNING: Package(s) not found: packaging

Issue Severity

Low: It annoys or frustrates me.