build: bump autopep8 from 2.3.0 to 2.3.1 in the testing group

Bumps the testing group with 1 update: [autopep8](https://github.com/hhatto/autopep8).


Updates `autopep8` from 2.3.0 to 2.3.1
- [Release notes](https://github.com/hhatto/autopep8/releases)
- [Commits](hhatto/autopep8@v2.3.0...v2.3.1)

---
updated-dependencies:
- dependency-name: autopep8
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: testing
...

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

pyproject.toml

@@ -59,7 +59,7 @@ jupyter = [
 
 tests = [
     "ansys-dpf-core==0.10.1",
-    "autopep8==2.3.0",
+    "autopep8==2.3.1",
     "matplotlib==3.9.0",
     "scipy==1.13.1",
     "pandas==2.2.2",