permission denied to create extension "pg_trgm" when use external postgresql (helm chart)

Summary

not real an issue as I found an easy workaround

when use external posgresql helm chart:

if I use as psql.username:gitlab, extension pg_trgm can not be created during install .

ERROR: permission denied to create extension "pg_trgm"
HINT : must be superuser to create this extension

To solve that I use user postgres (as it is a Superuser)