Fix colcon build error

[ChanJoon]

Error occurred on setuptools
UserWarning: Usage of dash-separated will not be supported in future versions

Change dash to underscore in setup.cfg (still not available in setuptools==64.4.0, but in 58.2.0)

[ChanJoon]

Hi, I cloned your repository and used colcon to build a package.
but there was following errors.

Starting >>> px4_offboard
/home/as06047/.local/lib/python3.8/site-packages/setuptools/dist.py:788: UserWarning: Usage of dash-separated 'script-dir' will not be supported in future versions. Please use the underscore name 'script_dir' instead
  warnings.warn(
/home/as06047/.local/lib/python3.8/site-packages/setuptools/dist.py:788: UserWarning: Usage of dash-separated 'install-scripts' will not be supported in future versions. Please use the underscore name 'install_scripts' instead
  warnings.warn(
--- stderr: px4_offboard                   
/home/as06047/.local/lib/python3.8/site-packages/setuptools/dist.py:788: UserWarning: Usage of dash-separated 'script-dir' will not be supported in future versions. Please use the underscore name 'script_dir' instead
  warnings.warn(
/home/as06047/.local/lib/python3.8/site-packages/setuptools/command/install.py:34: SetuptoolsDeprecationWarning: setup.py install is deprecated. Use build and pip and other standards-based tools.
  warnings.warn(
---
Finished <<< px4_offboard [3.54s]

Summary: 1 package finished [4.13s]
  1 package had stderr output: px4_offboard``

I found out that it was the problem of the version of setuptools.
After I replaced dashes to underscores and manually installed lower version of setuptools which is 58.2.0, colcon finally worked.(In the latest version, which is 64.4.0, colcon build failed due to using setup.py.)

[Jaeyoung-Lim]

@ChanJoon Thanks for the contribution.
Could you provide details on what system setup you are using?

I am a bit confused with the issue, since that part was generated through the ros2 package creator.

[ChanJoon]

I'm using
OS: Ubuntu 20.04
ROS2: Foxy
Python: 3.8.10

[Jaeyoung-Lim]

@ChanJoon Hmm, okay that is odd.
I will try to add a CI for ROS foxy to reproduce this problem.

[ChanJoon]

Thanks. It seems like the setup.py installation way is no more supported with the newer Python version.
there is opened issue colcon/colcon-core#454

Anyway, I'm currently learning a lot from you as an undergrad!

[Jaeyoung-Lim]

LGTM, thanks for the contribution!