enhanced .gitlab-ci.yml (using alpine instead of debian to trigger pipeline)

4 jobs for mohr in 3 minutes and 17 seconds (queued for 7 seconds)
Status Name Job ID Coverage
  Test
passed unittests_debian_10 #485310

00:02:15

82.0%
passed unittests_debian_latest #485311

00:03:16

82.0%
passed unittests_ubuntu_1804 #485312

00:02:07

82.0%
passed unittests_ubuntu_2004 #485313

00:03:07

82.0%