stack/slapos: version up passlib 1.7.4

should fix crypt issues with python 3.9
Status Job ID Name Coverage
  External
running Cloudooo.UnitTest-Master

12577:04:09

running ERP5.StandaloneDeploymentScriptTest-Debian.Buster.Master

12577:03:50

running SlapOS.Eggs.UnitTest-Jerome.Python2

12577:03:31

running SlapOS.Eggs.UnitTest-Jerome.Python3

12577:03:26

running SlapOS.SlapRunner.ResilienceTest-Master

12577:03:37

running SlapOS.SoftwareReleases.IntegrationTest-Master

12577:04:01

running Wendelin.StandaloneDeploymentScriptTest-Debian.Buster.Master

12577:04:22