[Completes #60810630] pull latest from current Git branch and push autoupdated SHAs to that branch, whether master, non-master or a detached HEAD (Jenkins)
(m) remove dead code
add function for auto-updating SHAs only in Jenkins (i.e., when HEAD is detached)
Merge pull request #17 from JamesLavin/60810630-autoupdating-shas-via-Jenkins-or-in-non-master-branch-deploys

60810630 autoupdating shas via jenkins or in non master branch deploys
separate updating of git branch & submodules from committing of submodule SHA changes
Merge pull request #18 from JamesLavin/62064492-move-SHA-auto-updating-out-of-prep-release

separate updating of git branch & submodules from committing of submodul...