Add urllib3's SSLError to expected Watcher exc

Seems like new requests lib is somehow raising
urllib3.exceptions.SSLError more often. This commit adds it to the
exceptions expected by the Watcher and silenced with a retry.

Closes-Bug: 1906498
Change-Id: I214c08c197483c00a5caecc47ef117cdd07a7652

kuryr_kubernetes/k8s_client.py

@@ -19,6 +19,7 @@ import os
 import ssl
 import time
 from urllib import parse
+import urllib3
 
 from oslo_log import log as logging
 from oslo_serialization import jsonutils
@@ -396,7 +397,8 @@ class K8sClient(object):
                             m = line_dict.get('object', {}).get('metadata', {})
                             resource_version = m.get('resourceVersion', None)
             except (requests.ReadTimeout, requests.ConnectionError,
-                    ssl.SSLError, requests.exceptions.ChunkedEncodingError):
+                    ssl.SSLError, requests.exceptions.ChunkedEncodingError,
+                    urllib3.exceptions.SSLError):
                 t = utils.exponential_backoff(attempt)
                 log = LOG.debug
                 if attempt > 0: