Update actions/upload-artifact action to v6 (#12)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/appimage.yml

@@ -31,7 +31,7 @@ jobs:
       - name: Make AppImage
         run: /bin/sh ./make-appimage.sh
       - name: Upload artifact
-        uses: actions/upload-artifact@330a01c490aca151604b8cf639adc76d48f6c5d4 # v5.0.0
+        uses: actions/upload-artifact@b7c566a772e6b6bfb58ed0dc250532a479d7789f # v6.0.0
         with:
           name: AppImage-${{ matrix.arch }}
           path: dist