client: allow using utf-8 usernames and passwords (#567)

* client: allow using utf-8 usernames and passwords

It looks like requests supports utf-8, but only if it is pre-encoded by the caller. Otherwise, it tries to encode both parameters using latin-1.

See
https://github.com/psf/requests/blob/a3ce6f007597f14029e6b6f54676c34196aa050e/src/requests/auth.py#L56-L60
psf/requests#3662
pallets/werkzeug#945

ara/clients/utils.py

@@ -22,7 +22,7 @@ def get_client(
     """
     auth = None
     if username is not None and password is not None:
-        auth = HTTPBasicAuth(username, password)
+        auth = HTTPBasicAuth(username.encode("utf-8"), password.encode("utf-8"))
 
     # Verify can be a bool (to ignore SSL verification or not)
     # or the path to a certificate authority