Bump typing

Author: shadchin

.travis.yml

@@ -31,7 +31,7 @@ matrix:
       dist: bionic
 
 install:
-  - pip install typing==3.7.4.1  # required for Python 3.3
+  - pip install typing==3.7.4.3  # required for Python 3.3
   - pip install tox==2.9.1
   - pip install virtualenv==15.2.0
   - pip install py==1.4.30