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

17282:48:59

running ERP5.StandaloneDeploymentScriptTest-Debian.Buster.Master

17282:48:41

running SlapOS.Eggs.UnitTest-Jerome.Python2

17282:48:22

running SlapOS.Eggs.UnitTest-Jerome.Python3

17282:48:16

running SlapOS.SlapRunner.ResilienceTest-Master

17282:48:28

running SlapOS.SoftwareReleases.IntegrationTest-Master

17282:48:51

running Wendelin.StandaloneDeploymentScriptTest-Debian.Buster.Master

17282:49:13