GitLab

squash testing pipeline

Closes #5

See merge request !17

(cherry picked from commit f95e687f)

1d8be482 split testing pipeline into 'build', 'test', and 'deploy'
a3e71132 change all CI job tags to 'demeter'
5e41aac9 ci: remove artifacts for 'debug' build
a8494170 ci: save built docs as artifacts
da3396cd ci: run 'update_dune' pipeline only on master branch

tests are allowed to fail until they are adapted.
'deploy' stage only contains building the docs.

see #5

(cherry picked from commit efc64606)