Merge pull request #1427 from marshmallow-code/dependabot/pip/mypy-0.740

Bump mypy from 0.730 to 0.740

Author: lafrech

setup.py

@@ -4,7 +4,7 @@
 EXTRAS_REQUIRE = {
     "tests": ["pytest", "pytz", "simplejson"],
     "lint": [
-        "mypy==0.730",
+        "mypy==0.740",
         "flake8==3.7.8",
         "flake8-bugbear==19.8.0",
         "pre-commit~=1.17",