Add lockfile support

[coretl]

We should add support for a lockfile generated by pip-compile as per:
https://github.com/coretl/copier-example/blob/e0522edda32d861885e5ea9211e263464b4d6461/pyproject.toml#L111-L119

Unfortunately this will not work with dependabot because of:
dependabot/dependabot-core#8381
dependabot/dependabot-core#5140

When these are fixed we can add lockfile support back in

[tpoliaw]

Now that PEP751 is accepted, should we be aiming to support pylock.toml files instead of the pip-tools compile versions? Maybe dependent on #246 and dependabot supporting the new format.

[coretl]

#248 converts this to use uv.lock, which is even less compatible with dependabot, but renovate supports it so we should use that instead...