From 41dcc421108fab67a1c41a6578fe242b516dbeaa Mon Sep 17 00:00:00 2001
From: Michael Tiemann <72577720+MichaelTiemannOSC@users.noreply.github.com>
Date: Mon, 15 Jan 2024 17:38:28 +1300
Subject: [PATCH] Update requirements_docs.txt

Based on this error message from the CI build:

```
Run sphinx-build -n -j auto -b html -d build/doctrees docs build/html
  sphinx-build -n -j auto -b html -d build/doctrees docs build/html
  shell: /usr/bin/bash -e {0}
  env:
    pythonLocation: /opt/hostedtoolcache/Python/3.9.18/x64
    LD_LIBRARY_PATH: /opt/hostedtoolcache/Python/3.9.18/x64/lib
Running Sphinx v4.5.0

Sphinx version error:
The sphinxcontrib.applehelp extension used by this project needs at least Sphinx v5.0; it therefore cannot be built with this version.
Error: Process completed with exit code 2.
```

bump sphinx to >= 5 (>4 only got us to 4.5).

Signed-off-by: Michael Tiemann <72577720+MichaelTiemannOSC@users.noreply.github.com>
---
 requirements_docs.txt | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/requirements_docs.txt b/requirements_docs.txt
index 8f4410960..68a96efb1 100644
--- a/requirements_docs.txt
+++ b/requirements_docs.txt
@@ -1,4 +1,4 @@
-sphinx>4
+sphinx>=5
 ipython<=8.12
 matplotlib
 mip>=1.13