[!46] Update CI config for master

See merge request !46
6 jobs from master in 2 minutes and 13 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Test
passed #42938
duneci
debian:10 clang-6-libcpp-17

00:02:13

passed #42937
duneci
debian:10 gcc-8-noassert-17

00:02:08

passed #42940
duneci
debian:9 clang-3.8-14

00:01:44

passed #42939
duneci
debian:9 gcc-6-14

00:01:29

passed #42941
duneci
ubuntu:16.04 gcc-5-14

00:01:13

passed #42942
duneci
ubuntu:18.04 clang-6-17

00:02:03