Merge branch 'add/buster' into 'master'

Add buster build

See merge request !4
4 jobs for master in 7 minutes and 18 seconds (queued for 6 seconds)
latest
Status Job ID Name Coverage
  Test Pre Build
passed #6779
test_build_script

00:01:26

 
  Build
passed #6780
build_nginx_buster

00:04:48

passed #6782
build_nginx_jessie

00:05:11

passed #6781
build_nginx_stretch

00:05:50