Merge branch 'ci-respdiff' into 'master'

CI: run respdiff using docker image in Gitlab CI

See merge request !275
4 jobs for <span class="ref-name">1.2-merge-master</span> in 91 minutes and 37 seconds (queued for 3 seconds)
Status Job ID Name Coverage
  Build
passed #8270
docker linux amd64
build:linux:amd64

00:00:24

 
  Test
passed #8272
docker linux amd64
deckard:linux:amd64

00:00:29

passed #8273
docker linux amd64
respdiff:linux:amd64

01:31:13

passed #8271
docker linux amd64
test:linux:amd64

00:00:21