Revert "Update prettier from 1.12.1 to 1.13.0 in addons/storysource"
Revert "Update prettier from 1.12.1 to 1.13.0 in addons/storysource"

This reverts commit a09bff9

storybooks/storybook,kadirahq/react-storybook,storybooks/storybook,storybooks/react-storybook,storybooks/storybook,storybooks/storybook,storybooks/react-storybook,kadirahq/react-storybook,storybooks/react-storybook,storybooks/storybook,storybooks/react-storybook,storybooks/storybook,storybooks/storybook