Add repo git hash into changelog

[hefee]

Currently it is quite cumbersome to find the repo git hash that was used to build a package. This is mostly important, when using unstable packages, that are not triggered by any git tags.

It would be helpful to have the repo git hash in the automatic changelog entry.
Additionally add an link to the jenkins job that generates the package?

The current workaround for e.g. kdevelop 5.6.1+p20.04+git20210121.0643-0:
Check if I have the correct build I need to check the artifacts if it is the correct dsc:
https://build.neon.kde.org/job/focal_unstable_extras_kdevelop_src/150/

Scan for the commit hash of kdevelop in:
https://build.neon.kde.org/job/focal_unstable_extras_kdevelop/150/console
06:43:28 > /home/neon/git-semaphore/git checkout -f 642fc99e0de8a3aba3a20762fb34eb9e3281c74e # timeout=60
06:43:28 Commit message: "Call canonical type before trying to deduce size of type"