Bump coactions/dynamic-matrix from 3 to 4

Bumps [coactions/dynamic-matrix](https://github.com/coactions/dynamic-matrix) from 3 to 4.
- [Release notes](https://github.com/coactions/dynamic-matrix/releases)
- [Commits](coactions/dynamic-matrix@v3...v4)

---
updated-dependencies:
- dependency-name: coactions/dynamic-matrix
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

.github/workflows/tox.yml

@@ -23,7 +23,7 @@ jobs:
     steps:
       - name: Determine matrix
         id: generate_matrix
-        uses: coactions/dynamic-matrix@v3
+        uses: coactions/dynamic-matrix@v4
         with:
           min_python: "3.9"
           max_python: "3.12"