Consider adding pyrosmsg UM ARM lab fork to CDCPD external directory

CDCPD depends on pyrosmsg to build, specifically, it depends on the UM ARM lab's fork of pyrosmsg and I believe that cloning and attempting to build with the official up-to-date main branch of pyrosmsg does not work.

For this reason, should we add the UM ARM Lab's fork of pyrosmsg to CDCPD like victor_hardware_interface, sdf_tools, etc.?