PivotalTracker Source Commits Endpoint

王权利请求将service-pivotaltracker合并到6-1-stable

Created by: ghost

Hi,

I've added a simple PivotalTracker Service for the Source Commits Endpoint (https://www.pivotaltracker.com/help/api/rest/v5#Source_Commits).

If there's something missing, please let me know.

Thanks for GitLab, it's a great OpenSource Project!

Best Regards

合并请求报告