pep8 blank lines fixes

flake8 --select W391,E302,E301,E304

autopep8 can't fix W391 even though it claims it can.
Fixed using a simple custom script.

weboob/capabilities/chat.py

@@ -57,6 +57,7 @@ class CapChat(Capability):
     """
     Websites with a chat system.
     """
+
     def iter_chat_messages(self, _id=None):
         """
         Iter messages.