exclude future incompatible jsonschema versions

Author: p1c2u

setup.cfg

@@ -25,7 +25,7 @@ python_requires = >= 2.7, != 3.0.*, != 3.1.*, != 3.2.*, != 3.3.*, != 3.4.*
 setup_requires =
     setuptools
 install_requires =
-    jsonschema
+    jsonschema<5.0.0
     openapi-schema-validator
     PyYAML>=5.1
     six