Bump soupsieve from 2.0.1 to 2.8.4 in /docs (#138)

Bumps [soupsieve](https://github.com/facelessuser/soupsieve) from 2.0.1 to 2.8.4.
- [Release notes](https://github.com/facelessuser/soupsieve/releases)
- [Commits](facelessuser/soupsieve@2.0.1...2.8.4)

---
updated-dependencies:
- dependency-name: soupsieve
  dependency-version: 2.8.4
  dependency-type: direct:production
...

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

Author: dependabot[bot]

docs/requirements.txt

@@ -42,7 +42,7 @@ recommonmark==0.6.0
 requests==2.33.0
 six==1.15.0
 snowballstemmer==2.0.0
-soupsieve==2.0.1
+soupsieve==2.8.4
 Sphinx==3.2.1
 sphinxcontrib-applehelp==1.0.2
 sphinxcontrib-devhelp==1.0.2