look for docker, not ts

Signed-off-by: Kristoffer Dalby <[email protected]>

integration/dns_test.go

@@ -269,7 +269,7 @@ func TestValidateResolvConf(t *testing.T) {
 				"HEADSCALE_DNS_NAMESERVERS_GLOBAL": "",
 			},
 			wantConfCompareFunc: func(t *testing.T, got string) {
-				assert.NotContains(t, got, "100.100.100.100")
+				assert.Contains(t, got, "Generated by Docker Engine")
 			},
 		},
 		{