cythonplus: Fix python version

12 jobs for master in 0 seconds
Status Job ID Name Coverage
  External
failed Cloudooo.UnitTest-Master

00:07:01

passed ERP5.StandaloneDeploymentScriptTest-Debian.Buster.Master

08:52:33

passed ERP5.StandaloneDeploymentScriptTest-Debian.Stretch

02:04:51

passed SlapOS-Master.StandaloneDeploymentScriptTest-Debian.Stretch

00:51:42

passed SlapOS.Eggs.UnitTest-Master.Python2

00:12:17

passed SlapOS.Eggs.UnitTest-Master.Python3

00:13:23

passed SlapOS.KVM.ResilienceTest-Master

00:20:16

passed SlapOS.SlapRunner.ResilienceTest-Master

00:22:28

failed SlapOS.SlapRunner.ResilienceTest-Master.ERP5

00:22:10

failed SlapOS.SoftwareReleases.IntegrationTest-Master

06:13:35

passed Wendelin.StandaloneDeploymentScriptTest-Debian.Buster

08:57:05

passed Wendelin.StandaloneDeploymentScriptTest-Debian.Stretch

08:45:07