revert pyyaml requirement version

Joshua Reed · Joshua Reed · commit 9aca116d0dcc · 2019-02-26T08:39:04.000-05:00
diff --git a/setup.py b/setup.py
@@ -69,7 +69,7 @@ def run_tests(self):
     },
     install_requires=[
         "jsonschema<3",
-        "PyYAML>=4.2b1",
+        "PyYAML>=3.13",
         "six",
         'pathlib;python_version=="2.7"',
     ],
