[Atlassian] Issue of not using proxies inside rest client session (#1488)

* Add proxies to request session

Adds the provided proxies to the request session after creation.

* Delete trailing whitespace

Delete trailing whitespace for codestyle

* Update rest_client.py

Author: flok

atlassian/rest_client.py

@@ -119,6 +119,10 @@ def __init__(
             self._session = requests.Session()
         else:
             self._session = session
+
+        if proxies is not None:
+            self._session.proxies = self.proxies
+
         if backoff_and_retry and int(urllib3.__version__.split(".")[0]) >= 2:
             # Note: we only retry on status and not on any of the
             # other supported reasons