Postgres: Add support for scram sha 256 authentication (#18397)

Allow datasource connection to postgres with password "scram-sha-256" 
authentification.

Fixes #14662

vendor/github.com/lib/pq/buf.go

@@ -66,7 +66,7 @@ func (b *writeBuf) int16(n int) {
 }
 
 func (b *writeBuf) string(s string) {
-	b.buf = append(b.buf, (s + "\000")...)
+	b.buf = append(append(b.buf, s...), '\000')
 }
 
 func (b *writeBuf) byte(c byte) {