upgrade colcon-cargo in pixi.toml for windows CI

[knmcguire]

In this PR of colcon-cargo, colcon-core version has been locked to be higher than 0.19: https://github.com/colcon/colcon-cargo/pull/59

Since the pixi.toml on the ros2 repo locks the colcon-cargo pypi to be less than 0.18 this is causing a dependency issue.

This PR fixes our CI temporary but a PR needs to be made to ROS2 repo pixi.toml file at least to fix this in the long term.