Bump nbsphinx from 0.8.8 to 0.8.9 (#320)

Bumps [nbsphinx](https://github.com/spatialaudio/nbsphinx) from 0.8.8 to 0.8.9.
- [Release notes](https://github.com/spatialaudio/nbsphinx/releases)
- [Changelog](https://github.com/spatialaudio/nbsphinx/blob/master/NEWS.rst)
- [Commits](spatialaudio/nbsphinx@0.8.8...0.8.9)

---
updated-dependencies:
- dependency-name: nbsphinx
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Fabian Zills <46721498+PythonFZ@users.noreply.github.com>

pyproject.toml

@@ -20,7 +20,7 @@ pandas = "^1.4.2"
 pytest = "^7.1.2"
 sphinx-rtd-theme = "^1.0.0"
 jupyterlab = "^3.4.2"
-nbsphinx = "^0.8.8"
+nbsphinx = "^0.8.9"
 nbsphinx-link = "^1.3.0"
 numpydoc = "^1.3.1"
 sphinx-copybutton = "^0.5.0"