Merge pull request #480 from p1c2u/dependabot/pip/mypy-0.991

Bump mypy from 0.971 to 0.991

Author: p1c2u

poetry.lock

@@ -90,7 +90,7 @@ sphinx = "^4.0.2"
 sphinx-rtd-theme = "^0.5.2"
 strict-rfc3339 = "^0.7"
 webob = "*"
-mypy = "^0.971"
+mypy = "^0.991"
 starlette = "^0.23.1"
 httpx = "^0.23.3"