build(deps): update matplotlib requirement in /requirements

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@v3.2.0...v3.7.3)

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

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

requirements/visual.txt

@@ -1,5 +1,5 @@
 # NOTE: the upper bound for the package version is only set for CI stability, and it is dropped while installing this package
 #  in case you want to preserve/enforce restrictions on the latest compatible version, add "strict" as an in-line comment
 
-matplotlib >=3.2.0, <=3.7.2
+matplotlib >=3.2.0, <=3.7.3
 SciencePlots >= 2.0.0, <= 2.1.0