updated citation for release

- [ ] Is it mergable
- [ ] Did it pass the tests?
- [ ] If it introduce new functionality in scripts/ is it tested?
  Check for code coverage.
- [ ] Is it well formatted? Look at `pep8`/`pylint`, `cppcheck`, and
  `make doc` output. Use `autopep8` and `astyle -A10` if needed.
- [ ] Is it documented in the Changelog?