Update sphinxcontrib-htmlhelp requirement from <=2.0.1 to <=2.0.5

Updates the requirements on [sphinxcontrib-htmlhelp](https://github.com/sphinx-doc/sphinxcontrib-htmlhelp) to permit the latest version.
- [Release notes](https://github.com/sphinx-doc/sphinxcontrib-htmlhelp/releases)
- [Changelog](https://github.com/sphinx-doc/sphinxcontrib-htmlhelp/blob/2.0.5/CHANGES)
- [Commits](sphinx-doc/sphinxcontrib-htmlhelp@1.0.0...2.0.5)

---
updated-dependencies:
- dependency-name: sphinxcontrib-htmlhelp
  dependency-type: direct:production
...

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

tests/requirements.txt

@@ -12,7 +12,7 @@ pytest-timeout>=1.4.2
 sphinx-toolbox[testing]>=2.13.0b3
 sphinxcontrib-applehelp<=1.0.4
 sphinxcontrib-devhelp<=1.0.2
-sphinxcontrib-htmlhelp<=2.0.1
+sphinxcontrib-htmlhelp<=2.0.5
 sphinxcontrib-jsmath<=1.0.1
 sphinxcontrib-qthelp<=1.0.3
 sphinxcontrib-serializinghtml<=1.1.5