Set up check in the sun deploy command for Friday
Set up check in the sun deploy command for Friday

Summary: Created a check in the sun deploy handler for Friday. If Friday, prompts the user to supply a different command for very small changes.

Test Plan: - Run tests on local khan-sun instance

Reviewers: benkraft, kevindangoor

Reviewed By: benkraft

Subscribers: kevindangoor

Differential Revision: https://phabricator.khanacademy.org/D35812

Khan/slack-deploy-hooks,Khan/slack-deploy-hooks