Use a gitea compatible implementation

.gitea/workflows/build-debian-package.yml

@@ -27,7 +27,7 @@ jobs:
         run: dpkg-deb --root-owner-group --build ./alumnihub_10.0_amd64
       - name: "Upload .deb"
         run: curl --user ${{ secrets.CI_RUNNER_USER }}:${{ secrets.CI_RUNNER_TOKEN }} --upload-file ./alumnihub_10.0_amd64.deb https://git.kocoder.xyz/api/packages/Diplomarbeit-Absolventenverein/debian/pool/trixie/main/upload
-      - uses: actions/upload-artifact@v4
+      - uses: https://github.com/christopherHX/gitea-upload-artifact@v4
         with:
           # A file, directory or wildcard pattern that describes what to upload
           # Required.