[3.6] Bump mypy-extensions from 0.4.1 to 0.4.2 (#4139)

dependabot-preview[bot] · web-flow · commit d361272f6085 · 2019-10-04T09:49:37.000Z
diff --git a/requirements/ci.txt b/requirements/ci.txt
@@ -1,6 +1,6 @@
 setuptools-git==1.2
 mypy==0.720; implementation_name=="cpython"
-mypy-extensions==0.4.1; implementation_name=="cpython"
+mypy-extensions==0.4.2; implementation_name=="cpython"
 freezegun==0.3.12
 
 -r ci-wheel.txt
