Bump actions/upload-artifact from 5 to 6

Bumps [actions/upload-artifact](https://github.com/actions/upload-artifact) from 5 to 6.
- [Release notes](https://github.com/actions/upload-artifact/releases)
- [Commits](actions/upload-artifact@v5...v6)

---
updated-dependencies:
- dependency-name: actions/upload-artifact
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

.github/workflows/python-publish.yml

@@ -33,7 +33,7 @@ jobs:
           python -m build
 
       - name: Upload distributions
-        uses: actions/upload-artifact@v5
+        uses: actions/upload-artifact@v6
         with:
           name: release-dists
           path: dist/

.github/workflows/tests.yml

@@ -40,13 +40,13 @@ jobs:
           coverage-badge -o coverage.svg
 
       - name: Upload Badge
-        uses: actions/upload-artifact@v5
+        uses: actions/upload-artifact@v6
         with:
           name: coverage-badge-${{ matrix.python-version }}.svg
           path: coverage.svg
 
       - name: Upload Report
-        uses: actions/upload-artifact@v5
+        uses: actions/upload-artifact@v6
         with:
           name: coverage_report_${{ matrix.python-version }}
           path: htmlcov