go template: fix: update statement for composite primary keys is broken
go template: fix: update statement for composite primary keys is broken

The generated Update SQL statement for tables that had composite primary
keys were invalid.
The columns in the WHERE clause where concatenated with an ", " instead
of " AND ".

In the generated where clause the primary keys are concatenated with an , instead of AND.

knq/xo,knq/xo,knq/xo