Declare packaging as install requirement (fixes #2022)

[ducroq]

Adds packaging>=21.0 to install_requires in setup.cfg.

Why

weaviate-client imports from packaging import version at module load in two places:

• weaviate/exceptions.py:9
• weaviate/proto/v1/__init__.py:12

Until v4.20.4 the dependency was satisfied transitively through deprecation, which was removed in v4.20.5 (#1999, "remove unmaintained deprecation package, use stdlib instead"). On environments that don't get packaging from somewhere else — slim Python container images are the canonical case — the first import weaviate now fails with ModuleNotFoundError: No module named 'packaging'. Reproducible on every release from 4.20.5 onwards.

Reproduction (no longer fails after this PR)

FROM python:3.12-slim
RUN pip install --no-cache-dir weaviate-client==4.21.0
RUN python -c "import weaviate"

Version pin

>=21.0 is conservative — packaging.version.Version has been stable since v17.0. Happy to widen or tighten if you have a preferred lower bound.

Notes

• No code change beyond the dependency declaration; existing imports are unchanged.
• Closes weaviate-client 4.20.5+ imports packaging without declaring it as a dependency #2022.
• This is my first PR to this repo. Will sign the CLA when prompted.

[orca-security-eu]

Orca Security Scan Summary

Status	Check	Issues by priority
Passed	Infrastructure as Code	0   0   0   0	View in Orca
Passed	SAST	0   0   0   0	View in Orca
Passed	Secrets	0   0   0   0	View in Orca
Passed	Vulnerabilities	0   0   0   0	View in Orca

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[dirkkul]

Thank you! Can you also add it here: requirements-devel.txt - I will then merge after you've agreed to the CLA!

[ducroq]

Done — added packaging==26.2 to requirements-devel.txt (matching the recent stable version in your install_requires range). New commit pushed.

Picked 26.2 since it's the version currently resolved in our own deploy chain and aligns with your existing pins; happy to adjust to whatever version your CI standardises on.

[ducroq]

I agree to the Weaviate CLA.