feat: Update `uv_build` to 0.12 when using `--meta=uv`

[ldej]

Summary

uv 0.12.0 is now the latest stable release on PyPI (released after 0.11.x). Following the existing cadence of bumping the emitted uv_build pin to track the latest uv minor, it would be great to update the --meta=uv template to emit uv_build>=0.12.0,<0.13.0.

Current state

The template currently emits the 0.11 pin:

• openapi_python_client/templates/pyproject_uv.toml.jinja

  requires = ["uv_build>=0.11.0,<0.12.0"]

• Snapshot test that would need updating: end_to_end_tests/metadata_snapshots/uv.pyproject.toml

Running openapi-python-client generate --meta uv ... against 0.29.0 produces:

[build-system]
requires = ["uv_build>=0.11.0,<0.12.0"]
build-backend = "uv_build"

Context

This continues the existing pattern of tracking each new uv minor:

• Update uv_build to 0.9 #1352 — Update uv_build to 0.9 (Nov 3, 2025)
• feat: Update uv_build 0.10 when using --meta=uv #1396 — Update uv_build to 0.10 (Feb 9, 2026)
• feat: Update uv_build to 0.11 when using --meta=uv #1434 — Update uv_build to 0.11 (May 11, 2026)

Happy to open a PR for this if it would help. Thanks!