Merge branch 'add/buster' into 'master'

Add buster build

See merge request !4
4 jobs for master in 7 minutes and 19 seconds (queued for 3 seconds)
latest
Status Job ID Name Coverage
  Test Pre Build
passed #4903
test_build_script

00:01:24

 
  Build
passed #4904
build_nginx_buster

00:04:53

passed #4906
build_nginx_jessie

00:05:53

passed #4905
build_nginx_stretch

00:04:27