Hi,

Whilst working on the Reproducible Builds effort [0], we noticed that
sphinx-needs could not be built reproducibly.

This is because the documentation (via the sphinx.ext.duration) Sphinx
extension, generates a sphinx-reading-durations.json file. This does
not seem to be used by the docs itself, so can be removed.

Patch attached that simply removes this file. I did try disabling its
generation by passing another -D option in SPHINXOPT but this did not
work; perhaps you will have better luck.

 [0] https://reproducible-builds.org/


Regards,