Update mypy from 0.770 to 0.780
diff --git a/tools/requirements_mypy.txt b/tools/requirements_mypy.txt
index 988ffe8..857c788 100644
--- a/tools/requirements_mypy.txt
+++ b/tools/requirements_mypy.txt
@@ -1,3 +1,3 @@
-mypy==0.770
+mypy==0.780
 mypy-extensions==0.4.3
 typed-ast==1.4.1