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

17312:27:18

running ERP5.StandaloneDeploymentScriptTest-Debian.Buster.Master

17312:26:59

running SlapOS.Eggs.UnitTest-Jerome.Python2

17312:26:40

running SlapOS.Eggs.UnitTest-Jerome.Python3

17312:26:34

running SlapOS.SlapRunner.ResilienceTest-Master

17312:26:46

running SlapOS.SoftwareReleases.IntegrationTest-Master

17312:27:09

running Wendelin.StandaloneDeploymentScriptTest-Debian.Buster.Master

17312:27:31