STY: check Python import sorting in CI

Author: davidesarra

.github/workflows/lint.yml

@@ -7,7 +7,7 @@ on:
     branches:
       - master
 jobs:
-  python_formatting_check:
+  python_linting:
     runs-on: ubuntu-latest
     steps:
     - name: Setup Python
@@ -18,5 +18,7 @@ jobs:
       uses: actions/checkout@v2
     - name: Install dev dependencies
       run: pip install -r requirements/dev_requirements.txt
-    - name: Check that Python files are formatted correctly
+    - name: Check order of Python imports
+      run: isort --check-only --diff --quiet .
+    - name: Check formatting of Python files
       run: black --check --diff .