This seems to be most appropriate way to ensure consistency between
release tarballs and public presentation on ReadTheDocs.
Previous attempt with removing docutils constraint, which relied on pip
depedency solver to pick the same packages as in CI was flawed. RTD
installs a bit different set of packages so it was inherently
unreliable.
As a result RTD pulled in sphinx-rtd-theme==0.4.3 while CI
had 1.0.0, and this inconsistency caused Table of Contents in Release
Notes to render incorrectly. Previous solution was to downgrade
docutils to < 0.17, but I think we should rather pin exact versions.
For the long history of messing with versions read also
isc-projects/bind9@2a8eda0084isc-projects/images@d4435b97beisc-projects/bind9@6a2daddf5b
6088ba3837