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] <support@github.com>

Author: dependabot[bot]

.github/workflows/cmake.yml

@@ -151,7 +151,7 @@ jobs:
           echo "Release directory contents:"
           ls -la "${{ env.RELEASES_DIR }}/"
       - name: Upload artifacts
-        uses: actions/upload-artifact@v5
+        uses: actions/upload-artifact@v6
         with:
           name: ${{ matrix.os }}-${{matrix.arch}}-${{ env.BUILD_TYPE }}
           path: ${{ env.RELEASES_DIR }}
@@ -196,7 +196,7 @@ jobs:
           tree "${{ env.RELEASES_DIR }}/"
 
       - name: Upload universal artifact
-        uses: actions/upload-artifact@v5
+        uses: actions/upload-artifact@v6
         with:
           name: macos-latest-universal-${{ env.BUILD_TYPE }}
           path: ${{ env.RELEASES_DIR }}

.github/workflows/debian.yml

@@ -80,7 +80,7 @@ jobs:
           lintian -i ${{ env.RELEASES_DIR }}/Qt-App.deb || true
 
       - name: Upload Debian packages
-        uses: actions/upload-artifact@v5
+        uses: actions/upload-artifact@v6
         with:
           name: debian-packages
           path: ${{ env.RELEASES_DIR }}