Fix vendored calls

Author: pradyunsg

src/pip/_vendor/__init__.py

@@ -75,7 +75,6 @@ def vendored(modulename):
     vendored("pep517")
     vendored("pkg_resources")
     vendored("progress")
-    vendored("pytoml")
     vendored("retrying")
     vendored("requests")
     vendored("requests.exceptions")
@@ -108,4 +107,7 @@ def vendored(modulename):
     vendored("requests.packages.urllib3.util.timeout")
     vendored("requests.packages.urllib3.util.url")
     vendored("resolvelib")
+    vendored("toml")
+    vendored("toml.encoder")
+    vendored("toml.decoder")
     vendored("urllib3")