fix: handle missing requests_mock.compat import gracefully

Author: allrob23

stackinabox/util/requests_mock/core.py

@@ -17,14 +17,18 @@
 from requests.adapters import HTTPAdapter
 from urllib3.response import HTTPResponse
 import requests_mock
-import requests_mock.compat
 import requests_mock.response
 import six
 
 from stackinabox.stack import StackInABox
 from stackinabox.util import deprecator
 from stackinabox.util.requests_mock import reqcallable
 
+try:
+    import requests_mock.compat
+except ImportError:
+    pass
+
 
 logger = logging.getLogger(__name__)