Merge branch 'add/buster' into 'master'

Add buster build

See merge request !4
4 jobs for master in 7 minutes and 43 seconds (queued for 2 seconds)
latest
Status Job ID Name Coverage
  Test Pre Build
passed #4638
test_build_script

00:01:34

 
  Build
passed #4639
build_nginx_buster

00:04:03

passed #4641
build_nginx_jessie

00:06:08

passed #4640
build_nginx_stretch

00:06:04