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

18309:19:58

running ERP5.StandaloneDeploymentScriptTest-Debian.Buster.Master

18309:19:40

running SlapOS.Eggs.UnitTest-Jerome.Python2

18309:19:21

running SlapOS.Eggs.UnitTest-Jerome.Python3

18309:19:15

running SlapOS.SlapRunner.ResilienceTest-Master

18309:19:27

running SlapOS.SoftwareReleases.IntegrationTest-Master

18309:19:50

running Wendelin.StandaloneDeploymentScriptTest-Debian.Buster.Master

18309:20:12