Avoid importing pkg_resources

[bluetech]

Hypothesis recently started importing pkg_resources which is notoriously slow to import. A better alternative these days is to use importlib.metadata, added in Python 3.8, or its backport importlib_metadata. Doing so would look something like this (completely untested, just to get the idea across):

diff --git a/hypothesis-python/src/hypothesis/entry_points.py b/hypothesis-python/src/hypothesis/entry_points.py
index 8cc4137ba..a5d670143 100644
--- a/hypothesis-python/src/hypothesis/entry_points.py
+++ b/hypothesis-python/src/hypothesis/entry_points.py
@@ -20,9 +20,18 @@ custom types, running the relevant code when *hypothesis* is imported instead of
 your package.
 """
 
-import pkg_resources
+try:
+    if sys.version_info >= (3, 8):
+        from importlib import metadata as importlib_metadata
+    else:
+        import importlib_metadata
+except ImportError:
+    import pkg_resources
 
-
-def run():
-    for entry_point in pkg_resources.iter_entry_points("hypothesis"):
-        entry_point.load()  # pragma: no cover
+    def run():
+        for entry_point in pkg_resources.iter_entry_points("hypothesis"):
+            entry_point.load()  # pragma: no cover
+else:
+    def run():
+        for entry_point in importlib_metadata.entry_points().get("hypothesis", []):
+            entry_point.load()  # pragma: no cover