Bump mypy to 0.790

The currently used version 0.740 throws syntax errors when used with
python 3.9.

Change-Id: If5cd0da2d5a77126e9ac4c4d6db7a6552f1bd067

1 files changed, 1 insertions, 1 deletions

diff --git a/tox.ini b/tox.ini
index 97aa3e64d..7a1802d33 100644
--- a/tox.ini
+++ b/tox.ini
@@ -55,7 +55,7 @@ install_command = pip install {opts} {packages}
 # type checking on the world - just on ourselves.
 deps =
   flake8
-  mypy<0.740
+  mypy<0.790
   openapi-spec-validator
 commands =
   flake8 {posargs}