update windows build to Python 3.7

Lib/site-packages/pkg_resources/extern/__init__.py

@@ -6,6 +6,7 @@ class VendorImporter:
     A PEP 302 meta path importer for finding optionally-vendored
     or otherwise naturally-installed packages from root_name.
     """
+
     def __init__(self, root_name, vendored_names=(), vendor_pkg=None):
         self.root_name = root_name
         self.vendored_names = set(vendored_names)
@@ -47,7 +48,7 @@ class VendorImporter:
                 # on later Python versions to cause relative imports
                 # in the vendor package to resolve the same modules
                 # as those going through this importer.
-                if sys.version_info > (3, 3):
+                if prefix and sys.version_info > (3, 3):
                     del sys.modules[extant]
                 return mod
             except ImportError:
@@ -67,5 +68,6 @@ class VendorImporter:
         if self not in sys.meta_path:
             sys.meta_path.append(self)
 
-names = 'packaging', 'six'
+
+names = 'packaging', 'pyparsing', 'six', 'appdirs'
 VendorImporter(__name__, names).install()