Use persist_to_workspace in CircleCi instead of cache for repo

[saraojelind]

Instead of using cache to load repo in each job, use persist_to_workspace since the code base should be used in all jobs and will always be updated between builds

Wagtail-Pipit/{{cookiecutter.project_name}}/.circleci/config.yml

Lines 60 to 63 in 41f274d

	- save_cache:
	key: v1-repo-{{ .Branch }}-{{ .Environment.CIRCLE_SHA1 }}
	paths:
	- .

Read more about workspaces here