add sync script

sync-from-upstream

@@ -0,0 +1,10 @@
+#!/bin/bash
+
+echo "Fetching from upstream"
+git fetch https://gitlab.com/redhat/centos-stream/release-engineering/pungi-centos.git centos-9-stream
+echo "Formatting patch and applying..."
+git format-patch --stdout -1 FETCH_HEAD | sed -e 's|centos/|rocky/|' | git apply
+echo "!! DIFF OF CHANGES !!"
+git --no-pager diff HEAD
+
+echo "You may now commit and push."