pgtype.OID type should only be used for scanning and encoding values

It was a mistake to use it in other contexts. This made interop
difficult between pacakges that depended on pgtype such as pgx and
packages that did not like pgconn and pgproto3. In particular this was
awkward for prepared statements.

This is preparation for removing pgx.PreparedStatement in favor of
pgconn.PreparedStatement.

batch.go

@@ -4,14 +4,13 @@ import (
 	"context"
 
 	"github.com/jackc/pgconn"
-	"github.com/jackc/pgtype"
 	errors "golang.org/x/xerrors"
 )
 
 type batchItem struct {
 	query             string
 	arguments         []interface{}
-	parameterOIDs     []pgtype.OID
+	parameterOIDs     []uint32
 	resultFormatCodes []int16
 }
 
@@ -24,7 +23,7 @@ type Batch struct {
 // Queue queues a query to batch b. query can be an SQL query or the name of a prepared statement. parameterOIDs and
 // resultFormatCodes should be nil if query is a prepared statement. Otherwise, parameterOIDs are required if there are
 // parameters and resultFormatCodes are required if there is a result.
-func (b *Batch) Queue(query string, arguments []interface{}, parameterOIDs []pgtype.OID, resultFormatCodes []int16) {
+func (b *Batch) Queue(query string, arguments []interface{}, parameterOIDs []uint32, resultFormatCodes []int16) {
 	b.items = append(b.items, &batchItem{
 		query:             query,
 		arguments:         arguments,