Install missing stubs for mypy 0.900 (#762)

* Install missing stubs for mypy 0.900

* Update mypy issue

tox.ini

@@ -73,6 +73,9 @@ deps =
     lxml
     # required for more thorough type declarations
     keyring >= 22.3
+    # consider replacing with `mypy --install-types` when
+    # https://github.com/python/mypy/issues/10600 is resolved
+    types-requests
 commands =
     mypy --html-report mypy --txt-report mypy {posargs:twine}
     python -c 'with open("mypy/index.txt") as f: print(f.read())'