GitHub Action to lint Python code

Test results: https://github.com/cclauss/DesktopAssitant/actions

.github/workflows/lint_python.yml

@@ -0,0 +1,23 @@
+name: lint_python
+on: [pull_request, push]
+jobs:
+  lint_python:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-python@v2
+      - run: pip install --upgrade pip wheel
+      - run: pip install bandit black codespell flake8 flake8-bugbear
+                         flake8-comprehensions isort mypy pytest pyupgrade safety
+      - run: bandit --recursive --skip B311,B605 .
+      - run: black --check . || true
+      - run: codespell
+      - run: flake8 . --count --max-complexity=19 --max-line-length=88 --show-source --statistics
+      - run: isort --check-only --profile black .
+      - run: pip install -r requirements.txt || pip install --editable . || true
+      - run: mkdir --parents --verbose .mypy_cache
+      - run: mypy --ignore-missing-imports --install-types --non-interactive .
+      - run: pytest . || true
+      - run: pytest --doctest-modules . || true
+      - run: shopt -s globstar && pyupgrade --py36-plus **/*.py
+      - run: safety check