Update lock file docs to point to uv

[matthewfeickert]

cvmfs-venv/README.md

Lines 269 to 277 in 1c34151

	* As the Python version tied to the virtual environment is provided by LCG view, any changes to the LCG view version require setting up the Python virtual environment from scratch.
	- It is highly advised that your environment be controlled with strict `requirements.txt` and lock files (e.g. generated from [`pip-tools`][pip-tools] using `pip-compile`) making it reproducible and easy to setup again as a consequence.
	- Example:
	```console
	(venv) $ python -m pip install --upgrade pip-tools
	(venv) $ echo "scipy==1.11.3" > requirements.txt # define high level requirements
	(venv) $ pip-compile --generate-hashes --output-file requirements.lock requirements.txt # Generate full environment lock file
	(venv) $ python -m pip install --no-deps --require-hashes --only-binary :all: --requirement requirements.lock # secure-install for reproducibility
	```

Should talk about uv