Merge branch 'add/buster' into 'master'

Add buster build

See merge request !4
4 jobs for master in 7 minutes and 1 second (queued for 2 seconds)
latest
Status Job ID Name Coverage
  Test Pre Build
passed #6421
test_build_script

00:01:20

 
  Build
passed #6422
build_nginx_buster

00:04:24

passed #6424
build_nginx_jessie

00:05:38

passed #6423
build_nginx_stretch

00:05:40