Update nbsphinx requirement from <0.9.0,>=0.8.5 to >=0.8.5,<0.10.0 (#757

)

Updates the requirements on [nbsphinx](https://github.com/spatialaudio/nbsphinx) to permit the latest version.
- [Release notes](https://github.com/spatialaudio/nbsphinx/releases)
- [Changelog](https://github.com/spatialaudio/nbsphinx/blob/master/NEWS.rst)
- [Commits](spatialaudio/nbsphinx@0.8.5...0.9.0)

---
updated-dependencies:
- dependency-name: nbsphinx
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

requirements/docs.txt

@@ -6,7 +6,7 @@ sphinx-rtd-theme>=1.0.0, <2.0.0
 sphinxcontrib-apidoc>=0.3.0, <0.4.0
 sphinxcontrib-bibtex>=2.1.0, <3.0.0
 myst-parser>=0.14, <0.19
-nbsphinx>=0.8.5, <0.9.0
+nbsphinx>=0.8.5, <0.10.0
 sphinx_design==0.3.0  # Pinning for now as sphinx_design is v.new and still in flux.
 ipykernel>=5.1.0, <7.0.0 # required for executing notebooks via nbsphinx
 ipython>=7.2.0, <9.0.0 # required for executing notebooks nbsphinx