`string_to_table` fails with Postgres < 14

[yoninachmany]

asyncpg.exceptions.UndefinedFunctionError: function string_to_table(text, unknown) does not exist
HINT:  No function matches the given name and argument types. You might need to add explicit type casts.

https://github.com/developmentseed/tipg/blob/main/tipg/sql/dbcatalog.sql#L131-L139

Result of running uvicorn tipg.main:app

[vincentsarago]

string_to_table was added in postgres 14 😓 (https://pgpedia.info/s/string_to_table.html)

cc @bitner