[requirements] Update beat.backend.python minimal version to 1.7.9

4 jobs for 64_add_optionnal_environment_entry_to_database in 16 minutes and 43 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Build
passed #201572
docker-build
build_linux_36

00:13:58

64.0%
passed #201573
docker-build
build_linux_37

00:13:52

64.0%
passed #201570
macosx
build_macosx_36

00:16:43

64.0%
passed #201571
macosx
build_macosx_37

00:16:34

63.0%