fixed warning regarding _ vs - when building with colcon and updated README.md

[jacobsayono]

1. Added notes based off your video tutorial!

2. Here's the warning message that we can get rid of:

Starting >>> ball_tracker
/usr/lib/python3/dist-packages/setuptools/dist.py:723: UserWarning: Usage of dash-separated 'script-dir' will not be supported in future versions. Please use the underscore name 'script_dir' instead
  warnings.warn(
/usr/lib/python3/dist-packages/setuptools/dist.py:723: UserWarning: Usage of dash-separated 'install-scripts' will not be supported in future versions. Please use the underscore name 'install_scripts' instead
  warnings.warn(

[jacobsayono]

I will help write some notes regarding the nodes as I get to understand the code better!

Note: I could add in the README that setuptools needs to be downgraded to remove the following warnings:

--- stderr: ball_tracker                                                          
/usr/lib/python3/dist-packages/setuptools/command/easy_install.py:158: EasyInstallDeprecationWarning: easy_install command is deprecated. Use build and pip and other standards-based tools.
  warnings.warn(
/usr/lib/python3/dist-packages/setuptools/command/install.py:34: SetuptoolsDeprecationWarning: setup.py install is deprecated. Use build and pip and other standards-based tools.
  warnings.warn(
---

I simply did pip install setuptools==58.2.0 to remove the warnings. Solution came from:
https://answers.ros.org/question/396439/setuptoolsdeprecationwarning-setuppy-install-is-deprecated-use-build-and-pip-and-other-standards-based-tools/