Install modular typeshed types for dependent packages

Mypy was warning about this. Types are now stored in types- packages,
so we need to install them before running type checking.

Author: cmatthew

tox.ini

@@ -18,6 +18,10 @@ skip_install = true
 deps =
     mypy >= 0.910
     sqlalchemy-stubs
+    types-setuptools
+    types-PyYAML
+    types-certifi
+
 commands =
     # Nowhere close to passing yet, but nice to have. The option
     # --no-incremental is currently needed to suppress warnings about