Updated .pre-commit-config.yaml to self-update its dependencies

Pre-commit will now automatically also run on any raised PRs. This will ensure committed code will always stay consistent.

{{cookiecutter.project_slug}}/.pre-commit-config.yaml

@@ -26,3 +26,10 @@ repos:
       - id: flake8
         args: ['--config=setup.cfg']
         additional_dependencies: [flake8-isort]
+
+
+# sets up .pre-commit-ci.yaml to ensure pre-commit dependencies stay up to date
+ci:
+    autoupdate_schedule: weekly
+    skip: []
+    submodules: false