build(deps-dev): bump sphinx-gallery from 0.19.0 to 0.20.0 in /_package

Bumps [sphinx-gallery](https://github.com/sphinx-gallery/sphinx-gallery) from 0.19.0 to 0.20.0.
- [Release notes](https://github.com/sphinx-gallery/sphinx-gallery/releases)
- [Changelog](https://github.com/sphinx-gallery/sphinx-gallery/blob/master/CHANGES.rst)
- [Commits](sphinx-gallery/sphinx-gallery@v0.19.0...v0.20.0)

---
updated-dependencies:
- dependency-name: sphinx-gallery
  dependency-version: 0.20.0
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

_package/pyproject.toml

@@ -50,7 +50,7 @@ doc = [
     "sphinx-autodoc-typehints==3.2.0",
     "sphinx-copybutton==0.5.2",
     "sphinx-notfound-page==1.1.0",
-    "sphinx-gallery==0.19.0",
+    "sphinx-gallery==0.20.0",
 ]
 [tool.flit.module]
 name = "pyconverter.generatedcommands"