I couldn't get my container started with postgress running but I had an idea:
I started the upgrade process with Lemmy-Easy-Deploy,
canceled out of it before it removed the containers,
ran sudo docker exec -i lemmy-easy-deploy-postgres-1 psql -U lemmy -c "alter user lemmy with password 'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx'"
with the password set in my env
file,
then restarted the upgrade process. It's running again.