bumped pyyaml as per github security

2019-01-14 00:16:09 -05:00 · 2019-01-14 00:16:09 -05:00 · a476856550
--- a/requirements.txt
+++ b/requirements.txt
@ -77,7 +77,7 @@ pytest==3.6.0
 pytest-cov==2.5.1
 python-dateutil==2.6.1
 pytz==2018.5
-PyYAML==3.13
+PyYAML==4.2b1
 requests==2.20.1
 requests-toolbelt==0.8.0
 responses==0.9.0