Merge branch 'add/debian-image' into 'master'

Introduce slim image for WP.org plugin deploys

See merge request !12
13 jobs for master in 1 minute and 25 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Test
passed #2883
lint-dockerfile

00:01:25

passed #2884
lint-shell-script

00:01:16

 
  Deploy
manual #2886
allowed to fail manual
build-debian-buster-build-master
manual #2888
allowed to fail manual
build-debian-jessie-build-master
manual #2887
allowed to fail manual
build-debian-stretch-build-master
manual #2889
allowed to fail manual
build-debian-wp-org-deploy-build-master
manual #2885
allowed to fail manual
build-golang-master
manual #2895
allowed to fail manual
build-php-5.3-master
manual #2894
allowed to fail manual
build-php-5.6-master
manual #2893
allowed to fail manual
build-php-7.0-master
manual #2892
allowed to fail manual
build-php-7.1-master
manual #2891
allowed to fail manual
build-php-7.2-master
manual #2890
allowed to fail manual
build-php-7.3-master