Add types-atomicwrites as extras to mypy pre-commit hook

This is a windows only dependency, which explains why it was missed until now.

.pre-commit-config.yaml

@@ -58,6 +58,7 @@ repos:
           - py>=1.8.2
           - attrs>=19.2.0
           - packaging
+          - types-atomicwrites
           - types-toml
           - types-pkg_resources
 -   repo: local