build(deps): bump github.com/jackc/pgtype from 1.7.0 to 1.8.1

Bumps [github.com/jackc/pgtype](https://github.com/jackc/pgtype) from 1.7.0 to 1.8.1.
- [Release notes](https://github.com/jackc/pgtype/releases)
- [Changelog](https://github.com/jackc/pgtype/blob/master/CHANGELOG.md)
- [Commits](https://github.com/jackc/pgtype/compare/v1.7.0...v1.8.1)

---
updated-dependencies:
- dependency-name: github.com/jackc/pgtype
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

vendor/github.com/jackc/pgproto3/v2/authentication_ok.go

@@ -2,6 +2,7 @@ package pgproto3
 
 import (
 	"encoding/binary"
+	"encoding/json"
 	"errors"
 
 	"github.com/jackc/pgio"
@@ -14,6 +15,9 @@ type AuthenticationOk struct {
 // Backend identifies this message as sendable by the PostgreSQL backend.
 func (*AuthenticationOk) Backend() {}
 
+// Backend identifies this message as an authentication response.
+func (*AuthenticationOk) AuthenticationResponse() {}
+
 // Decode decodes src into dst. src must contain the complete message with the exception of the initial 1 byte message
 // type identifier and 4 byte message length.
 func (dst *AuthenticationOk) Decode(src []byte) error {
@@ -37,3 +41,12 @@ func (src *AuthenticationOk) Encode(dst []byte) []byte {
 	dst = pgio.AppendUint32(dst, AuthTypeOk)
 	return dst
 }
+
+// MarshalJSON implements encoding/json.Marshaler.
+func (src AuthenticationOk) MarshalJSON() ([]byte, error) {
+	return json.Marshal(struct {
+		Type string
+	}{
+		Type: "AuthenticationOK",
+	})
+}