[dependabot] Bump sphinx-copybutton

Bumps the docs group with 1 update in the /docs directory: [sphinx-copybutton](https://github.com/executablebooks/sphinx-copybutton).


Updates `sphinx-copybutton` from 0.5.1 to 0.5.2
- [Release notes](https://github.com/executablebooks/sphinx-copybutton/releases)
- [Changelog](https://github.com/executablebooks/sphinx-copybutton/blob/master/CHANGELOG.md)
- [Commits](executablebooks/sphinx-copybutton@v0.5.1...v0.5.2)

---
updated-dependencies:
- dependency-name: sphinx-copybutton
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: docs
...

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

docs/requirements.txt

@@ -4,7 +4,7 @@ recommonmark==0.7.1
 sphinx-rtd-theme==1.1.1
 docutils<0.18
 jinja2==3.1.4
-sphinx-copybutton==0.5.1
+sphinx-copybutton==0.5.2
 # pin some older versions that are compatible with sphinx 4.5
 sphinxcontrib-applehelp==1.0.3
 sphinxcontrib.devhelp==1.0.2