adds .gitlab-ci.yml

1 job for master in 12 seconds (queued for 1 second)
Status Job ID Name Coverage
  Test
failed #10278
doxygen
pages

00:00:12

 
Name Stage Failure
failed
pages Test
$ make -C doc
make: Entering directory '/builds/dkrz-sw/yaxt/doc'
cd .. && ./scripts/generate_doc.pl configure.ac \
doc/Doxyfile.in doc/Doxyfile && \
doxygen doc/Doxyfile
/bin/sh: ./scripts/generate_doc.pl: not found
make: Leaving directory '/builds/dkrz-sw/yaxt/doc'
make: *** [Makefile:3: html/index.html] Error 127
ERROR: Job failed: exit code 2