Make this compatible with older GraphQL 3.1 versions (#43)

Author: Cito

src/graphql_relay/connection/connection.py

@@ -10,13 +10,30 @@
     GraphQLFieldResolver,
     GraphQLInt,
     GraphQLList,
-    GraphQLNamedOutputType,
     GraphQLNonNull,
     GraphQLObjectType,
     GraphQLString,
     Thunk,
 )
 
+try:
+    from graphql import GraphQLNamedOutputType
+except ImportError:  # GraphQL < 3.1.7
+    from graphql import (
+        GraphQLEnumType,
+        GraphQLInterfaceType,
+        GraphQLScalarType,
+        GraphQLUnionType,
+    )
+
+    GraphQLNamedOutputType = Union[  # type: ignore
+        GraphQLScalarType,
+        GraphQLObjectType,
+        GraphQLInterfaceType,
+        GraphQLUnionType,
+        GraphQLEnumType,
+    ]
+
 try:
     from typing import Protocol
 except ImportError:  # Python < 3.8

tox.ini

@@ -1,5 +1,5 @@
 [tox]
-envlist = py3{6,7,8,9,10}, black, flake8, mypy, manifest
+envlist = py3{6,7,8,9,10}, black, flake8, mypy, manifest, core310
 isolated_build = true
 
 [gh-actions]
@@ -36,6 +36,16 @@ deps = check-manifest>=0.47,<1
 commands =
     check-manifest -v
 
+[testenv:core310]
+basepython = python3.9
+deps =
+    graphql-core==3.1.0
+    pytest>=6.2,<7
+    pytest-asyncio>=0.16,<1
+    pytest-describe>=2,<3
+commands =
+    pytest tests {posargs}
+
 [testenv]
 deps =
     pytest>=6.2,<7