add migration for pg_create_subscription grant

[encima]

What kind of change does this PR introduce?

Feature

What is the current behavior?

Non superusers are unable to create subscriptions

What is the new behavior?

For 16 and above, this is possible as long as pg_create_subscription is granted by superuser to a role

Additional context

Unsure if handling the version check in the migration is the best choice but it is the most automated way

[steve-chavez]

Please let's merge #1521 before this one. We're adding new tests and we need to ensure this one is passing. (I can help to modify tests if something fails here).

[soedirgo]

Blocked on #1521

[steve-chavez]

#1521 was merged, please rebase here.

[samrose]

#1521 was merged, please rebase here.

@steve-chavez just did a rebase on develop and push now on this branch

[samrose]

Will get this into staging to test by tomorrow hopefully @encima

[samrose]

@encima this PR will likely need to have this test split up for the major versions https://github.com/supabase/postgres/blob/feat/subscription-create/nix/tests/sql/roles.sql

as we have done for instance with https://github.com/supabase/postgres/blob/feat/subscription-create/nix/tests/sql/z_15_ext_interface.sql and z_17_ext_interface.sql z_orioledb-17_ext_interface.sql for example

This will help the change pass the Nix CI build where these tests are run

@steve-chavez might be interested in this too as he had comments in the test that read

-- TODO: this exclusion is to maintain compat with pg17, we should cover it

https://github.com/supabase/postgres/blob/feat/subscription-create/nix/tests/sql/roles.sql#L14

[samrose]

@encima might need to refactor the tests first. Looking into that now

resolved

resolved