doc/requirements.txt: add sphinx_rtd_theme
This should fix the ReadTheDocs build
Turns out it was quite trivial: https://readthedocs.org/projects/knot-resolver/builds/23075949/
Self sign-up has been disabled due to increased spam activity. If you want to get access, please send an email to a project owner (preferred) or at gitlab(at)nic(dot)cz. We apologize for the inconvenience.
This should fix the ReadTheDocs build
Turns out it was quite trivial: https://readthedocs.org/projects/knot-resolver/builds/23075949/