fix ruff

Author: matteius

tests/integration/test_install_basic.py

@@ -799,7 +799,6 @@ def test_install_respects_lockfile_versions(pipenv_instance_pypi):
         c = p.pipenv("graph --json")
         assert c.returncode == 0
 
-        import json
         graph_data = json.loads(c.stdout)
         for entry in graph_data:
             if entry["package"]["package_name"] == "sh":