Fix argument of pg_create_logical_replication_slot for slot name

Fix argument of pg_create_logical_replication_slot for slot name

All attributes and arguments using a slot name map to the data type
"name", but this function has been using "text".  This is cosmetic, as
even if text is used then the slot name would be truncated to 64
characters anyway and stored as such.  The documentation already said
so and the function already assumed that the argument was of this type
when fetching its value.

Bump catalog version.

Author: Sawada Masahiko
Discussion: https://postgr.es/m/CAD21AoADYz_-eAqH5AVFaCaojcRgwpo9PW=u8kgTMys63oB8Cw@mail.gmail.com