Add '+upstream' suffix to published deb version (#102)

Using a debian version suffix which falls late alphabetically appears to
give our packages preference by apt. If a user enables a repository
which distributes packages created by OSRF or ROS, it is likely that
they wish to use these packages instead of the ones packaged by their
platform.

stdeb.cfg

@@ -4,3 +4,4 @@ Conflicts3: python-osrf-pycommon
 Suite3: focal jammy noble bookworm trixie
 X-Python3-Version: >= 3.8
 No-Python2:
+Upstream-Version-Suffix: +upstream