ci: configure mypy to be run as part of CI

Author: a-ungurianu

setup.cfg

@@ -64,6 +64,10 @@ test =
     gevent>=1.2 ; implementation_name!='pypy'
     eventlet>=0.17.1 ; implementation_name!='pypy'
 
+typing =
+    mypy
+    types-mock
+
 eventlet =
     eventlet>=0.17.1
 

tox.ini

@@ -5,7 +5,7 @@ requires=
     tox-wheel>=0.6.0
 skip_missing_interpreters=True
 envlist =
-    pep8,black,
+    pep8,black,mypy,
     gevent,eventlet,sasl,
     docs,
     pypy3
@@ -58,3 +58,10 @@ deps =
 usedevelop = True
 commands = black --check {posargs: {toxinidir}/kazoo {toxinidir}/kazoo}
 
+[testenv:mypy]
+basepython = python3
+extras = alldeps
+deps = 
+    mypy
+usedevelop = True
+commands = mypy