Bump matplotlib from 3.8.0 to 3.8.1 in /envs

Bumps [matplotlib](https://github.com/matplotlib/matplotlib) from 3.8.0 to 3.8.1.
- [Release notes](https://github.com/matplotlib/matplotlib/releases)
- [Commits](matplotlib/matplotlib@v3.8.0...v3.8.1)

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

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

envs/requirements.txt

@@ -26,7 +26,7 @@ javabridge==1.0.19.post9+gc8c12b4
 kiwisolver==1.4.5
 lazy_loader==0.3
 markdown-it-py==3.0.0
-matplotlib==3.8.0
+matplotlib==3.8.1
 matplotlib-scalebar==0.8.1
 mdurl==0.1.2
 meshio==5.3.4