change `run_shell_cmd` to store command output in temporary file(s) by default + pass `RunShellCmdResult` instance to `RunShellCmdError` #3164

	name: Static Analysis
	on: [push, pull_request]

	permissions:
	contents: read # to fetch code (actions/checkout)

	concurrency:
	group: ${{format('{0}:{1}:{2}', github.repository, github.ref, github.workflow)}}
	cancel-in-progress: true

	jobs:
	python-linting:
	runs-on: ubuntu-20.04
	strategy:
	matrix:
	python-version: [3.6, 3.7, 3.8, 3.9, '3.10', '3.11']

	steps:
	- uses: actions/checkout@v3

	- name: set up Python
	uses: actions/setup-python@v4
	with:
	python-version: ${{ matrix.python-version }}

	- name: install Python packages
	run: \|
	pip install --upgrade pip
	pip install --upgrade flake8

	- name: Run flake8 to verify PEP8-compliance of Python code
	run: \|
	flake8

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