[PostgreSQL] fix pg_hba.conf for GitHub Codespaces

At Github Codespaces, `psql` was failing:

```
$ psql
psql: error: connection to server at "localhost" (::1), port 5432 failed: FATAL:  no pg_hba.conf entry for host "::1", user "postgres", database "postgres", SSL encryption
connection to server at "localhost" (::1), port 5432 failed: FATAL:  no pg_hba.conf entry for host "::1", user "postgres", database "postgres", no encryption
```

Apparently, the reason is that pg_hba.conf was only expecting IPv4 connections.

This adds support for IPv6-configured dev containers, by adding corresponding line into pg_hba.conf

src/postgresql/install.sh

@@ -65,6 +65,7 @@ chown -R postgres:postgres $PGDATA \
     && echo "listen_addresses = '*'" >> /etc/postgresql/${version_major}/main/postgresql.conf \
     && echo "data_directory = '$PGDATA'" >> /etc/postgresql/${version_major}/main/postgresql.conf \
     && echo "host   all all 0.0.0.0/0        trust" > /etc/postgresql/${version_major}/main/pg_hba.conf \
+    && echo "host   all all ::/0             trust" >> /etc/postgresql/${version_major}/main/pg_hba.conf \
     && sudo -H -u postgres sh -c "/usr/lib/postgresql/${version_major}/bin/initdb -D $PGDATA --auth-local trust --auth-host scram-sha-256" \
     && sudo /etc/init.d/postgresql start \
     && pg_isready -t 60