Update pytest from 3.8.2 to 3.9.1

Author: pyup-bot

requirements/default.txt

@@ -167,9 +167,9 @@ pyjexl==0.2.3 \
 pytest-django==3.4.3 \
     --hash=sha256:49e9ffc856bc6a1bec1c26c5c7b7213dff7cc8bc6b64d624c4d143d04aff0bcf \
     --hash=sha256:b379282feaf89069cb790775ab6bbbd2bd2038a68c7ef9b84a41898e0b551081
-pytest==3.8.2 \
-    --hash=sha256:7e258ee50338f4e46957f9e09a0f10fb1c2d05493fa901d113a8dafd0790de4e \
-    --hash=sha256:9332147e9af2dcf46cd7ceb14d5acadb6564744ddff1fe8c17f0ce60ece7d9a2
+pytest==3.9.1 \
+    --hash=sha256:10e59f84267370ab20cec9305bafe7505ba4d6b93ecbf66a1cce86193ed511d5 \
+    --hash=sha256:8c827e7d4816dfe13e9329c8226aef8e6e75d65b939bc74fda894143b6d1df59
 pytest-mock==1.10.0 \
     --hash=sha256:53801e621223d34724926a5c98bd90e8e417ce35264365d39d6c896388dcc928 \
     --hash=sha256:d89a8209d722b8307b5e351496830d5cc5e192336003a485443ae9adeb7dd4c0