Introduce Black to automate code formatting

platformio/commands/home/web.py

@@ -17,14 +17,12 @@ from twisted.web import static  # pylint: disable=import-error
 
 
 class WebRoot(static.File):
-
     def render_GET(self, request):
         if request.args.get("__shutdown__", False):
             reactor.stop()
             return "Server has been stopped"
 
-        request.setHeader("cache-control",
-                          "no-cache, no-store, must-revalidate")
+        request.setHeader("cache-control", "no-cache, no-store, must-revalidate")
         request.setHeader("pragma", "no-cache")
         request.setHeader("expires", "0")
         return static.File.render_GET(self, request)