Ubuntu Upgrade from 18.04 to 20.04 failed due to Postgres/Postgis package on removal blacklist.

Hello Community!

One of my Postgresql servers has been over the years through "in-place" update for last 6 years or so.  Currently stands at 18.04 w/ Postgres-12-Postgis 3.1, the server went through multiple version os Ubuntu and PostgreSQL .

I am trying to upgrade Ubuntu to 20.04 first before upgrading PostgreSQL, but failed with OS upgrade.  Here are the last few lines in /var/log/dist-upgrade/main.log after failed upgrade:

2021-11-09 08:35:50,044 DEBUG blacklist expr '^postgresql-.*[0-9][0-9].*' matches 'postgresql-12-postgis-3'

2021-11-09 08:35:50,044 DEBUG The package 'postgresql-12-postgis-3' is marked for removal but it's in the removal blacklist

2021-11-09 08:35:50,053 ERROR Dist-upgrade failed: 'The package 'postgresql-12-postgis-3' is marked for removal but it is in the removal blacklist.'

2021-11-09 08:35:50,055 DEBUG abort called

The offending package  'postgresql-12-postgis-3' corresponds my current Postgresql version.  Should I remove the package and proceed with OS upgrade?  I am at a loss... 

Thanks!

Bo