docs: ROS2 tutorial commands for building C++ nodes

[wjwwood]

Updated commands to include 'colcon-common-extensions' and modified build command syntax.

I assume this is what was intended originally since the new package was generated into a src folder and because of the arguments that come after pixi run build.

How Has This Been Tested?

I tested this locally on my personal macbook air.

AI Disclosure

No AI tools used.

Checklist:

• I have performed a self-review of my own code
• I have made corresponding changes to the documentation

[ruben-arts]

I just tested it, and it seems to be that we're just getting a newer cmake version there sends a message to the stderr saying :

--- stderr: my_cpp_package
CMake Deprecation Warning at CMakeLists.txt:1 (cmake_minimum_required):
  Compatibility with CMake < 3.10 will be removed from a future version of
  CMake.

  Update the VERSION argument <min> value.  Or, use the <min>...<max> syntax
  to tell CMake that the project requires at least <min> but has been updated
  to work with policies introduced by <max> or earlier.
---

This would be solved by lowering the cmake dependency or adding cmake_minimum_required(VERSION 3.10) to the CMakeLists.txt. As we're getting version 4.2.2 without more constraints.

However, this is presented as an error, it's isn't a blocking one.

We could make "cmake<4" the dependency for cmake or fix the error by letting people make the minimum cmake version 3.10.

What do you think?

[wjwwood]

Lowering the cmake version will avoid that warning, but ultimately that's something we'll need to fix upstream in ROS, so I wouldn't necessarily pin the version for this tutorial.

[wjwwood]

That being said, this tutorial does explicitly use ROS humble, which has a recommended cmake version (around cmake ~3.22), which you could pin to if you wanted, see: https://www.ros.org/reps/rep-2000.html#humble-hawksbill-may-2022-may-2027

[ruben-arts]

Thank you!