ci: Add Flake8 linting to notebooks

.github/workflows/flake8.yml

@@ -5,14 +5,14 @@ concurrency:
   cancel-in-progress: true
 
 on:
-   # Trigger the workflow on push or pull request,
-   # but only for the master branch
-   push:
-     branches:
-       - master
-   pull_request:
-     branches:
-       - master
+  # Trigger the workflow on push or pull request,
+  # but only for the master branch
+  push:
+    branches:
+      - master
+  pull_request:
+    branches:
+      - master
 
 jobs:
   flake8:
@@ -21,14 +21,16 @@ jobs:
 
     steps:
     - uses: actions/checkout@v4
-    - name: Set up Python 3.9
+    - name: Set up Python 3.12
       uses: actions/setup-python@v5
       with:
-        python-version: 3.9
+        python-version: 3.12
     - name: Install dependencies
       run: |
         python -m pip install --upgrade pip
         pip install flake8
+        pip install nbqa
     - name: Lint with flake8
       run: |
         flake8 --builtins=ArgumentError .
+        nbqa flake8 examples/