Move colcon from apt to pip

[piraka9011]

This PR moves the installation of colcon and associated extensions from apt to pip in order to lock down the version of colcon + extensions and avoid breaking changes from upstream.

Tests for this are being run here.

Signed-off-by: Anas Abou Allaban allabana@amazon.com

[thomas-moulard]

LGTM

[zmichaels11]

@piraka9011 🚢

[rotu]

Why are we pinning colcon versions?

It seems like this is likely to cause trouble since the tutorial recommends installing via either apt or pip3, and these pinned versions match neither release.

https://index.ros.org/doc/ros2/Tutorials/Colcon-Tutorial/

Are upstream colcon changes breaking the build a common problem?
fyi: @dirk-thomas

[rotu]

Here's the type of problems this causes when trying to use CI to test colcon changes:

https://github.com/rotu/colcon-cmake/runs/1022561615?check_suite_focus=true#step:8:6641

  ERROR:colcon.colcon_core.entry_point:Exception loading extension 'colcon_core.environment_variable.cmake_command': (colcon-core 0.5.5 (/usr/local/lib/python3.6/dist-packages), Requirement.parse('colcon-core>=0.5.6'))
  Traceback (most recent call last):
    File "/usr/local/lib/python3.6/dist-packages/colcon_core/entry_point.py", line 101, in load_entry_points
      extension_type = load_entry_point(entry_point)
    File "/usr/local/lib/python3.6/dist-packages/colcon_core/entry_point.py", line 143, in load_entry_point
      return entry_point.load()
    File "/usr/local/lib/python3.6/dist-packages/pkg_resources/__init__.py", line 2471, in load
      self.require(*args, **kwargs)
    File "/usr/local/lib/python3.6/dist-packages/pkg_resources/__init__.py", line 2494, in require
      items = working_set.resolve(reqs, env, installer, extras=self.extras)
    File "/usr/local/lib/python3.6/dist-packages/pkg_resources/__init__.py", line 790, in resolve
      raise VersionConflict(dist, req).with_context(dependent_req)
  pkg_resources.VersionConflict: (colcon-core 0.5.5 (/usr/local/lib/python3.6/dist-packages), Requirement.parse('colcon-core>=0.5.6'))