chore(deps): update dependency pytest-runner to v6

setup.py

@@ -5,7 +5,7 @@ import sys
 from setuptools import setup
 
 needs_pytest = {"pytest", "test", "ptr"}.intersection(sys.argv)
-pytest_runner = ["pytest-runner >=4.0,<5dev"] if needs_pytest else []
+pytest_runner = ["pytest-runner >=6,<7"] if needs_pytest else []
 
 
 def read(fname):