Cap the version of the psycopg2-binary dependency for Postgres.
Review Request #2264 — Created Sept. 23, 2021 and updated
`psycopg2-binary` 2.9 introduced some changes that broke timezone
management on older versions of Django (2.2 and older). This includes
us, and is described at https://github.com/psycopg/psycopg2/issues/1293.
Official guidance is to pin the version, so to avoid customer issues,
our wrapper package now pins `psycopg2-binary` to `<2.9`.
Tested that installing `ReviewBoard[postgres]` installed the right package.
Verified the fix with a customer. zklllllllllllllllllll
Reviewed at https://reviews.reviewboard.org/r/11723/