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

14825:27:18

running ERP5.StandaloneDeploymentScriptTest-Debian.Buster.Master

14825:27:00

running SlapOS.Eggs.UnitTest-Jerome.Python2

14825:26:41

running SlapOS.Eggs.UnitTest-Jerome.Python3

14825:26:35

running SlapOS.SlapRunner.ResilienceTest-Master

14825:26:47

running SlapOS.SoftwareReleases.IntegrationTest-Master

14825:27:10

running Wendelin.StandaloneDeploymentScriptTest-Debian.Buster.Master

14825:27:32