CNAME responses can occur with "Type: A" dns_sd_config requests (#8216)

Signed-off-by: Matt Berther <mattberther@users.noreply.github.com>

discovery/dns/dns.go

@@ -211,8 +211,10 @@ func (d *Discovery) refreshOne(ctx context.Context, name string, ch chan<- *targ
 			target = hostPort(addr.A.String(), d.port)
 		case *dns.AAAA:
 			target = hostPort(addr.AAAA.String(), d.port)
+		case *dns.CNAME:
+			// CNAME responses can occur with "Type: A" dns_sd_config requests.
 		default:
-			level.Warn(d.logger).Log("msg", "Invalid SRV record", "record", record)
+			level.Warn(d.logger).Log("msg", "Invalid record", "record", record)
 			continue
 		}
 		tg.Targets = append(tg.Targets, model.LabelSet{