Postgres no longer recognizes credentials in ".pgpass" file.

Heads-up: the v0.21.3 release bumped 'lib/pq' from 11.2 to 12.0, which breaks reading of the ".pgpass" file. A PR to fix this [is out](https://github.com/lib/pq/pull/1295) but it may be a while before it's approved, a new 'lib/pq' release is made, and then we see another dependency bump here. Leaving this issue here for anyone else running into the problem. Solutions are to set `PGPASSFILE="${HOME}/.pgpass"` in your env, or to revert to `usql` release 'v0.21.2'.