Fix entry points handling on 3.8, which does not have EntryPoint.module.

setup.py

@@ -130,6 +130,8 @@ def read_file(*path):
     setup_requires=[
     ],
     install_requires=[
+        # PyPA standard version and requirement handling.
+        'packaging',
         'perfmetrics >= 3.0.0',
         'zope.interface',
         'zope.dottedname',

src/relstorage/tests/test_zodburi.py

@@ -206,13 +206,16 @@ def _check_entry_point(self, name, cls, helper_cls):
                                         module="relstorage.zodburi_resolver",
                                         name=name,)
         else:
-            # Prior to 3.10, we have to do this all manually.
+            # Prior to 3.10, we have to do this all manually (keyword selection
+            # was introduced in 3.10). Prior to 3.9, there is no ``.module`` attribute,
+            # so we have to look at the entire ``.value``.
+            #
             ep_dict = entry_points()
             entry_point, = (
                 ep
                 for ep
                 in ep_dict['zodburi.resolvers']
-                if ep.name == name and ep.module == 'relstorage.zodburi_resolver'
+                if ep.name == name and ep.value.startswith('relstorage.zodburi_resolver:')
             )
 
         target = entry_point.load()