Add direct dependency on jsonschema (#868)

spiffworkflow-backend/pyproject.toml

@@ -79,6 +79,7 @@ flask-session = "^0.5.0"
 flask-oauthlib = "^0.9.6"
 celery = {extras = ["redis"], version = "^5.3.5"}
 celery-stubs = "^0.1.3"
+jsonschema = "^4.20.0"
 
 [tool.poetry.scripts]
 spiffworkflow-backend = "spiffworkflow_backend.__main__:main"
@@ -123,6 +124,9 @@ filterwarnings = [
     # flask_marshmallow/__init__.py:34
     # marshmallow_sqlalchemy/convert.py:17
     'ignore:distutils Version classes are deprecated. Use packaging.version instead.',
+    # connexion/json_schema.py:17
+    'ignore:jsonschema.exceptions.RefResolutionError is deprecated as of version 4.18.0',
+    'ignore:jsonschema.RefResolver is deprecated as of v4.18.0',
     # connexion/spec.py:50
     'ignore:Passing a schema to Validator.iter_errors is deprecated and will be removed in a future release',
     # connexion/decorators/validation.py:16