stricter mypy settings

Committed via https://github.com/asottile/all-repos

setup.cfg

diff --git a/setup.cfg b/setup.cfg
index fc57939..a5ad401 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -80,6 +80,8 @@
 disallow_incomplete_defs = true
 disallow_untyped_defs = true
 no_implicit_optional = true
+warn_redundant_casts = true
+warn_unused_ignores = true
 
 [mypy-testing.*]
 disallow_untyped_defs = false