Maintenance release 6

Features

process:

• kill_childs() has now an option to not kill childs, so we can use it as bare os.kill() replacement which handles PID reusage properly
• Refactored kill_childs() so we use signals when possible, to avoid race conditions that come with PID reusage
• Added get_absolute_path() that allows to find an executable path in PATH environment variable, in order to avoid shell=True calls with command_runner / subprocess
• Added get_processes_by_name() that allows to find processes by name, with default case ignore on Windows

file_utils

• log_on_perm_fn() now includes a check_permissions() call in order to have more debug material

Misc

• Added newer python versions to testing matrix
• Added black linter, moved all linting to Python 3.9 only