bpo-33131: Upgrade ensurepip to bundle pip 10.0.1 (GH-6546)


Upgrade ensurepip to bundle pip 10.0.1
(cherry picked from commit 0399cf9b5e370516e3d0aed6a63ff74aff5eadb5)

Co-authored-by: Paul Moore <p.f.moore@gmail.com>
diff --git a/Lib/ensurepip/__init__.py b/Lib/ensurepip/__init__.py
index 89ed1ef..49d74cd 100644
--- a/Lib/ensurepip/__init__.py
+++ b/Lib/ensurepip/__init__.py
@@ -14,7 +14,7 @@
 
 _SETUPTOOLS_VERSION = "39.0.1"
 
-_PIP_VERSION = "9.0.3"
+_PIP_VERSION = "10.0.1"
 
 _PROJECTS = [
     ("setuptools", _SETUPTOOLS_VERSION),
@@ -28,8 +28,8 @@
         sys.path = additional_paths + sys.path
 
     # Install the bundled software
-    import pip
-    return pip.main(args)
+    import pip._internal
+    return pip._internal.main(args)
 
 
 def version():