pipes import is obsolete since python 3.11

pipes is set for removal in 3.13

when using python >=3.11 a deprecation warning is triggered:

DeprecationWarning: 'pipes' is deprecated and slated for removal in Python 3.13

See also:

https://docs.python.org/3/library/pipes.html

https://peps.python.org/pep-0594/#pipes

Also used python from-import-as syntax for shellquote instead of the manual assignment