Remove deprecated pytest_runner

We are already using tox to bootstrap env and run tests.

Ref:
	- pypa/setuptools#1684
	- https://github.com/pytest-dev/pytest-runner#deprecation-notice

setup.py

@@ -16,7 +16,7 @@
     long_description = f.read()
 
 
-version = "0.1.0"
+version = "0.3.0"
 
 setup(
     name="pyramid_deferred_sqla",
@@ -52,6 +52,5 @@
         "venusian",
         "zope.sqlalchemy",
     ],
-    setup_requires=["pytest-runner"],
     extras_require={"dev": ["coverage", "pytest", "tox"], "lint": ["black"]},
 )