Bump actions/upload-artifact from 2 to 4

Bumps [actions/upload-artifact](https://github.com/actions/upload-artifact) from 2 to 4.
- [Release notes](https://github.com/actions/upload-artifact/releases)
- [Commits](https://github.com/actions/upload-artifact/compare/v2...v4)

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

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/snap.yml

@@ -75,7 +75,7 @@ jobs:
           mkdir artifact
           mv $artifact_name artifact
 
-      - uses: actions/upload-artifact@v2
+      - uses: actions/upload-artifact@v4
         if: env.UPLOAD_ARTIFACT == 'true'
         name: Upload artifact.
         with: