build(deps): bump actions/upload-artifact from 4 to 5

Bumps [actions/upload-artifact](https://github.com/actions/upload-artifact) from 4 to 5.
- [Release notes](https://github.com/actions/upload-artifact/releases)
- [Commits](actions/upload-artifact@v4...v5)

---
updated-dependencies:
- dependency-name: actions/upload-artifact
  dependency-version: '5'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

.github/workflows/main_fristenkalender.yml

@@ -40,7 +40,7 @@ jobs:
       - name: copy src dir to project root (dirty deployment hack)
         run: cp src/* ./ -r
       - name: Upload artifact for deployment job
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@v5
         with:
           name: python-app
           path: |