Export CPU times in seconds

Use the system's value for HZ (100 by default), which is the unit that
cgroups cpuacct statistics are using.
4 jobs for master in 2 minutes and 59 seconds (queued for 2 seconds)
Status Name Job ID Coverage
  Build Pkgsrc
passed build_pkgsrc:buster #16375

00:00:14

 
  Build Pkg
passed build_pkg:buster:amd64 #16376
amd64

00:00:40

passed build_pkg:buster:arm64 #16377
arm64

00:02:25

 
  Upload Pkg
passed upload_pkg #16378

00:00:17