[CI] Try introducing isort. (#3495)

.github/workflows/ruff.yml

@@ -25,10 +25,13 @@ jobs:
     - name: Install dependencies
       run: |
         python -m pip install --upgrade pip
-        pip install ruff==0.1.5 codespell==2.2.6 tomli==2.0.1
+        pip install ruff==0.1.5 codespell==2.2.6 tomli==2.0.1 isort==5.13.2
     - name: Analysing the code with ruff
       run: |
         ruff .
     - name: Spelling check with codespell
       run: |
-        codespell --toml pyproject.toml
+        codespell --toml pyproject.toml
+    - name: Run isort
+      run: |
+        isort . --check-only