chore(deps): Bump sphinx-notfound-page from 1.0.2 to 1.0.4 in /docs (openwallet-foundation#3464)

Bumps [sphinx-notfound-page](https://github.com/readthedocs/sphinx-notfound-page) from 1.0.2 to 1.0.4.
- [Changelog](https://github.com/readthedocs/sphinx-notfound-page/blob/main/CHANGELOG.rst)
- [Commits](readthedocs/sphinx-notfound-page@1.0.2...1.0.4)

---
updated-dependencies:
- dependency-name: sphinx-notfound-page
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

docs/requirements.txt

@@ -2,4 +2,4 @@
 sphinx==5.3.0
 sphinx_rtd_theme==1.3.0
 readthedocs-sphinx-search==0.3.2
-sphinx-notfound-page==1.0.2
+sphinx-notfound-page==1.0.4