Merge pull request #59 from p1c2u/fix/jsonschema-requirement-fix

jsonschema requirement fix

Author: p1c2u

setup.py

@@ -68,7 +68,7 @@ def run_tests(self):
         ]
     },
     install_requires=[
-        "jsonschema",
+        "jsonschema<3",
         "PyYAML>=4.2b1",
         "six",
         'pathlib;python_version=="2.7"',