Enable black in the workflow to check formatting

We don't format the code. It is up to the commiter to call black on its
own code. The workflow only checks that formatting is ok.

Signed-off-by: Guillaume <[email protected]>

.github/workflows/format.yaml

@@ -3,6 +3,20 @@ name: Check coding style
 on: [push]
 
 jobs:
+  black:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - name: Set up Python
+      uses: actions/setup-python@v2
+    - name: Install dependencies
+      run: |
+        python -m pip install --upgrade pip
+        pip install black
+        if [ -f requirements.txt ]; then pip install -r requirements.txt; fi
+    - name: black
+      run: |
+        black --unstable .
   pycodestyle:
     runs-on: ubuntu-latest
     steps:

setup.cfg

@@ -1,6 +1,9 @@
 [pycodestyle]
 max-line-length=120
-ignore=E261,E302,E305,E402,W503
+ignore=E203,E261,E302,E305,E402,E701,W503
 
 [pydocstyle]
 ignore=D100,D101,D102,D103,D104,D105,D106,D107,D203,D210,D212,D401,D403
+
+[tool.black]
+line-length=120