chore: update httpclient (#834)

* chore: update httpclient

Author: manisha1997

tests/unit/http/test_http_client.py

@@ -293,6 +293,7 @@ def test_session_not_preserved(self):
         self.assertEqual(response_2.content, "response_2")
 
 
+
 class MyVersion(Version):
     def __init__(self, domain):
         super().__init__(domain, "v1")

twilio/http/http_client.py

@@ -40,7 +40,7 @@ def __init__(
         self.session = Session() if pool_connections else None
         if self.session and max_retries is not None:
             self.session.mount("https://", HTTPAdapter(max_retries=max_retries))
-        if self.session is not None:
+        elif self.session is not None:
             self.session.mount(
                 "https://", HTTPAdapter(pool_maxsize=min(32, os.cpu_count() + 4))
             )