Uses the Debian/Ubuntu package for sphinxcontrib-spelling rather than from pip. This fixes the issue by virtue of being an older version. I think we should prefer these packages anyway for stability.
This issue looks to have been caused by sphinxcontrib-spelling needing docutils >= 0.18.1 but not declaring that as a requirement (see sphinx-contrib/spelling#212). The current ubuntu-latest appears to feature 0.17.1:
Uses the Debian/Ubuntu package for sphinxcontrib-spelling rather than from pip. This fixes the issue by virtue of being an older version. I think we should prefer these packages anyway for stability.
This issue looks to have been caused by sphinxcontrib-spelling needing
docutils >= 0.18.1but not declaring that as a requirement (see sphinx-contrib/spelling#212). The currentubuntu-latestappears to feature 0.17.1:Build test