--config-override parsing is too restrictive

[johnbcoughlin]

Description

The --config-override option cannot accept values with a = in them, such as a Dockerfile ENV key=val custom build step command.

Steps to reproduce

$ uv run tesseract build --config-override custom_build_steps='ENV mysecret=foo mykey=bar' examples/vectoradd
Usage: tesseract build [OPTIONS] SRC_DIR
Try 'tesseract build -h' for help.
╭─ Error ──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────╮
│ Invalid value for config_override: Invalid config override custom_build_steps=ENV mysecret=foo mykey=bar (must be `keypath=value`)               │
╰──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────╯

Logs

OS

Mac

Tesseract version

0.9.2.dev28+g9caa5db