v12 and pg_restore -f-

This is a "heads up" for others upgrading to v12. I found a solution for our
use case, but it'd be easy to miss this, even if you read the release notes.

I saw this and updated our scripts with pg_restore -f-
https://www.postgresql.org/docs/12/release-12.html
|In pg_restore, require specification of -f - to send the dump contents to standard output (Euler Taveira)
|Previously, this happened by default if no destination was specified, but that was deemed to be unfriendly.

What I didn't realize at first is that -f- has no special meaning in v11 - it
just writes a file called ./- And it's considered untennable to change
behavior of v11.

In our use, that was being piped to sed, which then saw nothing on its stdin
and just exits.. I changed our script to use pg_restore -f /dev/stdout, which
seems to be portable across postgres versions for the OS distribution we're
running. Unfortunately, I can't think of anything portable across *OS* or
useful to include in documentation. In the worst case, someone might need to
call pg_restore differently based on its version.

Justin