Update mypy to 0.790, and move dependencies to extras (#8583)

changelog.d/8583.misc

@@ -0,0 +1 @@
+Update `mypy` static type checker to 0.790.

setup.py

@@ -102,6 +102,8 @@ CONDITIONAL_REQUIREMENTS["lint"] = [
     "flake8",
 ]
 
+CONDITIONAL_REQUIREMENTS["mypy"] = ["mypy==0.790", "mypy-zope"]
+
 # Dependencies which are exclusively required by unit test code. This is
 # NOT a list of all modules that are necessary to run the unit tests.
 # Tests assume that all optional dependencies are installed.

tox.ini

@@ -160,9 +160,7 @@ commands=
 [testenv:mypy]
 deps =
     {[base]deps}
-    mypy==0.782
-    mypy-zope
-extras = all
+extras = all,mypy
 commands = mypy
 
 # To find all folders that pass mypy you run: