https://docs.aws.amazon.com/de_de/cli/latest/userguide/cli-configure-envvars.html
Set following environment variables:
S3='s3://mybucket/'
PGHOST='localhost:5432'
PGDATABASE='postgres'
PGUSER='postgres@postgres'
PGPASSWORD='password'
Backup will be stored in /pg_backup and copied to S3 afterwards