Update matplotlib requirement from <3.8,>=3.5.1 to >=3.5.1,<3.9

Updates the requirements on [matplotlib](https://github.com/matplotlib/matplotlib) to permit the latest version.
- [Release notes](https://github.com/matplotlib/matplotlib/releases)
- [Commits](matplotlib/matplotlib@v3.5.1...v3.8.1)

---
updated-dependencies:
- dependency-name: matplotlib
  dependency-type: direct:production
...

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

pyproject.toml

@@ -49,7 +49,7 @@ gui = [
     "Gooey>=1.0.8.1,<1.1"
 ]
 doc = [
-    "matplotlib>=3.5.1,<3.8",
+    "matplotlib>=3.5.1,<3.9",
     "myst-nb>=0.13.2,<0.18",
     "sphinx>=5.2.0,<7.3",
     "sphinxcontrib-httpdomain>=1.7.0,<1.9",