CI: Add pyflakes

This adds `pyflakes` for code linting in pre-commits.

This is performed via `flake8 --select=F`, skipping all other stylistic
checks of flake8 (which we perform with other tools such as black
and isort). Also, `flake8` supports `...  # noqa` annotations to
silence warnings from `pyflakes`.

.pre-commit-config.yaml

@@ -86,14 +86,14 @@ repos:
   - id: isort
     name: isort (python)
 
-# Python: Flake8 (checks only, does this support auto-fixes?)
-#- repo: https://github.com/PyCQA/flake8
-#  rev: 4.0.1
-#  hooks:
-#  - id: flake8
-#    additional_dependencies: &flake8_dependencies
-#      - flake8-bugbear
-#      - pep8-naming
+# Python: Flake8 (only for pyflake)
+- repo: https://github.com/PyCQA/flake8
+  rev: 6.1.0
+  hooks:
+  - id: flake8
+    additional_dependencies: &flake8_dependencies
+      - flake8-bugbear
+      - Flake8-pyproject
 #    exclude: ^(docs/.*|tools/.*)$
 # Alternatively: use autopep8?
 

pyproject.toml

@@ -5,3 +5,8 @@ requires = [
     "cmake>=3.20.0,<4.0.0"
 ]
 build-backend = "setuptools.build_meta"
+
+
+[tool.flake8]
+#ignore = ['E231', 'E241']
+select = ['F']