Add rawhide upstream sync script
1. Invoke the script as follows:
where upstream-repo is the path to the synced upstream git repo.
2. Watch the script run. If it proceeds to building the package, then
everything seems good and you just need to test the build after it
is complete. If it exits before the build (you'll know if you read
the output of the script) then manual intervention is required to
complete the sync. This will typically happen when a patch fails
to apply on the new sources.