Merge pull request #843 from adamtheturtle/pyup-update-vws-python-mock-2018.9.10.6-to-2018.9.23.1

Update vws-python-mock to 2018.9.23.1

Author: adamtheturtle

dev-requirements.txt

@@ -1,6 +1,6 @@
 PyYAML==3.13
 Pygments==2.2.0
-VWS-Python-Mock==2018.9.10.6
+VWS-Python-Mock==2018.9.23.1
 autoflake==1.2
 check-manifest==0.37
 codecov==2.0.15 # Upload coverage data