Log Message:
py-sphinxcontrib-bibtex: updated to 1.0.0

1.0.0:
* Drop Python 2.7 and 3.4 support (as upstream sphinx has dropped
  support for these as well).
* Add Python 3.8 support (contributed by hroncok).
* Update for Sphinx 2.x, and drop Sphinx 1.x support (as there is too
  much difference between the two versions).
* Non-bibtex citations will now no longer issue warnings
* Switch to codecov for coverage reporting.