Pin mypy==0.761

Signed-off-by: ulyssessouza <ulyssessouza@gmail.com>

Author: ulyssessouza

tox.ini

@@ -22,7 +22,7 @@ commands =
 skip_install = true
 deps =
   flake8
-  mypy
+  mypy==0.761
 commands =
   flake8 src tests
   mypy --python-version=3.8 src tests