Takes a pg_dump from a postgresql database, gzips the dump and uploads it to
Backblaze B2.
pg-b2 table_name bucket_name [ filename_prefix ]
For example, pg-b2 k3s k3s_dumps hourly/ will take a dump of the k3s table
and upload that dump to the hourly/k3s.pgdump.gz file in the k3s_dumps
bucket.
The dump is temporarily stored in $HOME/.pgb2_scratch/ (or
/tmp/.pgb2_scratch if $HOME is empty). This location can be overwritten by
via the $PGB2_SCRATCH_DIR environment variable.