build(deps): 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/next.yml

@@ -48,7 +48,7 @@ jobs:
      - name: build
        run: |
          scripts/build-muon.sh
-     - uses: actions/upload-artifact@v5
+     - uses: actions/upload-artifact@v6
        name: Upload artifacts
        with:
          name: samu-muon

.github/workflows/release.yml

@@ -48,7 +48,7 @@ jobs:
      - name: build
        run: |
          scripts/build-muon.sh
-     - uses: actions/upload-artifact@v5
+     - uses: actions/upload-artifact@v6
        name: Upload artifacts
        with:
          name: samu-muon