Git plugin: support to report some tags in the commit msg

[qiankehan]

In a commit msg, a developer could use these tags to give the credit to the people who help with the commit, such as:

• Co-developed-by:
• Reported-by:
• Tested-by:
• Reviewed-by:
• Suggested-by:

Mention these in the did report of git will provide a more complete report for the work.

[psss]

Sounds like a nice improvement. Another common header is Co-authored-by. Probably would be best to allow user to specify custom headers which should be reported in the config file. Pull requests welcome.