Bump openpyxl from 3.1.3 to 3.1.5 in /docs

Bumps [openpyxl](https://openpyxl.readthedocs.io) from 3.1.3 to 3.1.5.

---
updated-dependencies:
- dependency-name: openpyxl
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>

docs/requirements.txt

@@ -41,7 +41,7 @@ mdurl==0.1.2
     # via markdown-it-py
 myst-parser==3.0.1
     # via -r requirements.in
-openpyxl==3.1.3
+openpyxl==3.1.5
     # via -r requirements.in
 packaging==23.1
     # via sphinx