chore(deps): update actions/upload-artifact digest to b4b15b8

Author: msclock-bot[bot]

.github/workflows/ci.yml

@@ -447,7 +447,7 @@ jobs:
 
       - name: Upload test results
         if: failure()
-        uses: actions/upload-artifact@50769540e7f4bd5e21e526ee35c689e35e0d6874 # v4
+        uses: actions/upload-artifact@b4b15b8c7c6ac21ea08fcf65892d2ee8f75cf882 # v4
         with:
           name: valgrind-results
           path: out/valgrind-results.tar.gz