Make mypy succeed with imports on master.py

We get little benefit from our mypy QA checks at the moment, because we skip
imports. This patch is what's needed to make mypy succeed with imports on a
single file: master.py

It also updates mypy to the current version, and enables a QA check.

Mypy bugs I encountered:

dict.update with kwargs not supported:

https://github.com/python/mypy/issues/1031

property setters and getters must be adjacent:

https://github.com/python/mypy/issues/1465

1 files changed, 1 insertions, 1 deletions

diff --git a/mitmproxy/utils/typecheck.py b/mitmproxy/utils/typecheck.py
index e8e2121e..5df4ea4b 100644
--- a/mitmproxy/utils/typecheck.py
+++ b/mitmproxy/utils/typecheck.py
@@ -1,7 +1,7 @@
 import typing
 
 
-def check_type(name: str, value: typing.Any, typeinfo: type) -> None:
+def check_type(name: str, value: typing.Any, typeinfo: typing.Any) -> None:
     """
     This function checks if the provided value is an instance of typeinfo
     and raises a TypeError otherwise.