Add 'id' to github branchsource
Add 'id' to github branchsource

This is required so that pipeline jobs can find the tip of a branch
when a build is replayed.
See https://issues.jenkins-ci.org/browse/JENKINS-46290.

Change-Id: Ifa6d71aa343fcbde27b3a98b0eb574456550e32c

sillsdev/ci-builder-scripts,sillsdev/ci-builder-scripts,sillsdev/ci-builder-scripts