WIP [ci] add trigger for lecture build
Introduces a first pipeline to Dumux, which simply consists of a trigger to build dumux-lecture after a commit has been made to the master branch.
WPI because it depends on ci integration in dumux-lecture, currently assigned to @emmert.
- after merging in dumux-lecture, modify the lecture branch of the trigger to master
before merge, change rule to
$CI_COMMIT_BRANCH == $CI_DEFAULT_BRANCH