[fix] fix black version

mirage/http.py

@@ -65,7 +65,9 @@ class HTTPServer:
 
     async def create_server(self, ssl_ctx=None):
         self.handler = web.AppRunner(
-            self.app, keep_alive_on=False, access_log=log.access_logger,
+            self.app,
+            keep_alive_on=False,
+            access_log=log.access_logger,
         )
 
         self.port = find_unused_port()

requirements_dev.txt

 coveralls
 mypy
 pylint
-black
+black==20.8b1