cd /usr/lib/python3/dist-packages/colcon_python_setup_py/package_identification
sudo gedit python_setup_py.py
change line251: 'from setuptools.extern.packaging.specifiers import SpecifierSet',
to
'from packaging.specifiers import SpecifierSet',
cd /usr/lib/python3/dist-packages/colcon_python_setup_py/package_identification
sudo gedit python_setup_py.py
change line251: 'from setuptools.extern.packaging.specifiers import SpecifierSet',
to
'from packaging.specifiers import SpecifierSet',