build(deps): bump mypy from 0.780 to 0.781 (#726)

dependabot-preview[bot] · web-flow · commit 6e378f18919a · 2020-06-22T08:10:09.000Z
diff --git a/linter-requirements.txt b/linter-requirements.txt
@@ -1,6 +1,6 @@
 black==19.10b0
 flake8
 flake8-import-order
-mypy==0.780
+mypy==0.781
 flake8-bugbear>=19.8.0
 pep8-naming
