Make an empty commit if 50 days have elapsed since the last commit

[jamesgeorge007]

GitHub will stop running the cron-based trigger if no activity is found to happen on the repository for the past 60 days. Making an empty commit once in a while will prevent this behavior. A way to handle this is to calculate the time elapsed from the last commit's time and make an empty commit if it is more than 50 days.

Ref: https://github.com/gautamkrishnar/blog-post-workflow/issues/53