chore: introduce flake8-bugbear

The configuration is adapted from black and flask.

Author: weakish

.flake8

@@ -1,4 +1,6 @@
 [flake8]
-max-line-length = 88
-extend-ignore = E203
-exclude = build,docs
+ignore = E203, E266, E501, E722, W503
+max-line-length = 80
+max-complexity = 18
+select = B,C,E,F,W,T4,B9
+exclude = build,docs

.github/workflows/pythonpackage.yml

@@ -29,7 +29,7 @@ jobs:
         pip install -r requirements.txt
     - name: Lint with flake8
       run: |
-        pip install flake8
+        pip install flake8 flake8-bugbear
         # stop the build if there are Python syntax errors or undefined names
         flake8 . --count --select=E9,F63,F7,F82 --show-source --statistics
         # exit-zero treats all errors as warnings.