move pytest to extras-require

setup.py

@@ -102,11 +102,12 @@ setup(
         "loopy>=2021.1",
         "boxtree>=2018.1",
         "arraycontext",
-        "pytest>=2.3",
         "pyrsistent>=0.16.0",
-        "dataclasses>=0.7;python_version<='3.6'",
         "sympy>=0.7.2",
         "pymbolic>=2021.1",
         "pyvkfft>=2022.1",
     ],
+    extras_require={
+        "test": ["pytest>=2.3"],
+    },
 )