Don't use pgtype.Array with pgx/v5 driver

[earthboundkid]

What do you want to change?

pgtype.Array is very cumbersome to use and does not serialize to JSON well. It would be much more useful for pgtype.FlatArray to be the default.

What database engines need to be changed?

PostgreSQL

What programming language backends need to be changed?

Go

[earthboundkid]

Based on comments by JackC, I think the correct solution here is to just remove the use of pgtype.Array. I will open a PR to do that.

[earthboundkid]

Quoting JackC,

I don't know the context for the sqlc thing, but I'm a little surprised whenever I see pgtype.FlatArray or especially pgtype.Array used directly. Typically, pgx can directly work with []T, [][]T, etc. I only anticipated pgtype.Array being used directly if the application actually needed to work with non-standard starting indexes.

I agree. This is a regression in functionality from the v4 code generator, which used slices directly. My PR undoes the change.