caddy-frontend: Stabilize sort

We want to sort by filename, which is on second column. The previous value
here was just wrong.
28 jobs for master in 0 seconds
Status Job ID Name Coverage
  External
passed Cloudooo.UnitTest-Master

00:05:51

passed ERP5.StandaloneDeploymentScriptTest-Debian.Buster

09:24:32

passed ERP5.StandaloneDeploymentScriptTest-Debian.Buster.Master

07:58:47

passed ERP5.StandaloneDeploymentScriptTest-Debian.Stretch

00:35:20

passed SlapOS-Master.StandaloneDeploymentScriptTest-Debian.Buster

09:01:55

passed SlapOS-Master.StandaloneDeploymentScriptTest-Debian.Stretch

00:49:33

passed SlapOS.Eggs.UnitTest-Master.Python2

00:13:28

passed SlapOS.Eggs.UnitTest-Master.Python3

00:13:07

passed SlapOS.KVM.ResilienceTest-Master

00:20:25

passed SlapOS.SlapRunner.ResilienceTest-Master

00:22:20

failed SlapOS.SlapRunner.ResilienceTest-Master.ERP5

01:37:50

passed SlapOS.SoftwareReleases.IntegrationTest-Master

05:42:35

passed Wendelin.StandaloneDeploymentScriptTest-Debian.Buster

00:31:09

failed Wendelin.StandaloneDeploymentScriptTest-Debian.Buster.Master

13:32:23

passed Wendelin.StandaloneDeploymentScriptTest-Debian.Stretch

09:33:15

passed ERP5.StandaloneDeploymentScriptTest-Debian.Buster

08:46:22

passed ERP5.StandaloneDeploymentScriptTest-Debian.Stretch

00:44:55

passed SlapOS-Master.StandaloneDeploymentScriptTest-Debian.Buster

09:29:59

passed SlapOS-Master.StandaloneDeploymentScriptTest-Debian.Stretch

01:15:48

passed SlapOS.Eggs.UnitTest-Master.Python2

00:11:50

passed SlapOS.Eggs.UnitTest-Master.Python2

00:12:32

passed SlapOS.Eggs.UnitTest-Master.Python3

00:13:28

passed SlapOS.Eggs.UnitTest-Master.Python3

00:14:21

passed SlapOS.KVM.ResilienceTest-Master

00:20:08

passed SlapOS.SlapRunner.ResilienceTest-Master

00:22:41

failed SlapOS.SlapRunner.ResilienceTest-Master.ERP5

01:39:59

passed Wendelin.StandaloneDeploymentScriptTest-Debian.Buster

00:23:08

passed Wendelin.StandaloneDeploymentScriptTest-Debian.Stretch

08:32:02