ci: add style check with black

Signed-off-by: Nicolai Buchwitz <nb@tipi-net.de>

Author: nbuchwitz

.github/workflows/lint.yml

@@ -1,4 +1,4 @@
-name: Pylint
+name: Linting
 
 on: [push]
 
@@ -17,9 +17,12 @@ jobs:
     - name: Install dependencies
       run: >-
         python -m
-        pip install pylint
+        pip install pylint black
         --user
 
+    - name: Check coding style
+      run: black --check tests uhubctl
+
     - name: Analysing the code with pylint
       run: |
         find . -name '*.py' -exec pylint {} \;