[requires.io] dependency update

requires · requires · commit 8314561ad343 · 2017-08-18T06:41:23.000-05:00
diff --git a/test_requirements.txt b/test_requirements.txt
@@ -1,4 +1,4 @@
 pytest==3.2.1
 pytest-cov==2.5.1
-pytest-xdist==1.19.1
+pytest-xdist==1.20.0
 hypothesis==3.18.5
