Hint: PostgreSQL 13 issues when building gvmd or running pg_upgradecluster

Not directly related to building gvmd but if you get the following error with gvm-setup on Kali:

ERROR: The default postgresql version is not 13 required by libgvmd
Error: Use pg_upgradecluster to update your postgres cluster

please check the following posting for this GVM unrelated problem in your PostgreSQL / Kali setup / environment: