Restore access to the postgres user for the govuk_env_sync.sh script
Restore access to the postgres user for the govuk_env_sync.sh script

The sudoers config was changed, but access to the postgres user was
missed, so restore access so commands like pg_dump can be run.

alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet